KENR5099 06检修

KENR5099-06
November 2010
Systems Operation
Troubleshooting
Testing and Adjusting
CX28, CX31 and CX35
On-Highway Transmissions
Power Train Electronic Control System
EBW1-Up (Transmission)
B3X1-Up (Transmission)
T3X1-Up (Transmission)
W3X1-Up (Transmission)
SAFETY.CAT.COM
i03991620
Important Safety Information

Most accidents that involve product operation, maintenance and repair are caused by failure to observe
basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous
situations before an accident occurs. A person must be alert to potential hazards. This person should also
have the necessary training, skills and tools to perform these functions properly.
Improper operation, lubrication, maintenance or repair of this product can be dangerous and
could result in injury or death.
Do not operate or perform any lubrication, maintenance or repair on this product, until you have
read and understood the operation, lubrication, maintenance and repair information.
Safety precautions and warnings are provided in this manual and on the product. If these hazard warnings
are not heeded, bodily injury or death could occur to you or to other persons.
The hazards are identified by the “Safety Alert Symbol” and followed by a “Signal Word” such as
“DANGER”, “WARNING” or “CAUTION”. The Safety Alert “WARNING” label is shown below.
The meaning of this safety alert symbol is as follows:

Attention! Become Alert! Your Safety is Involved.
The message that appears under the warning explains the hazard and can be either written or pictorially
presented.
A non-exhaustive list of operations that may cause product damage are identified by “NOTICE” labels
on the product and in this publication.
Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard.
The warnings in this publication and on the product are, therefore, not all inclusive. You must
not use this product in any manner different from that considered by this manual without first
satisfying yourself that you have considered all safety rules and precautions applicable to the
operation of the product in the location of use, including site-specific rules and precautions
applicable to the worksite. If a tool, procedure, work method or operating technique that is not
specifically recommended by Caterpillar is used, you must satisfy yourself that it is safe for you
and for others. You should also ensure that the product will not be damaged or become unsafe by
the operation, lubrication, maintenance or repair procedures that you intend to use.
The information, specifications, and illustrations in this publication are on the basis of information that
was available at the time that the publication was written. The specifications, torques, pressures,
measurements, adjustments, illustrations, and other items can change at any time. These changes can
affect the service that is given to the product. Obtain the complete and most current information before you
start any job. Cat dealers have the most current information available.
When replacement parts are required for this

product Caterpillar recommends using Cat re-
placement parts or parts with equivalent speci-
fications including, but not limited to, physical
dimensions, type, strength and material.
Failure to heed this warning can lead to prema-

ture failures, product damage, personal injury or
death.
In the United States, the maintenance, replacement, or repair of the emission control devices and
systems may be performed by any repair establishment or individual of the owner's choosing.
KENR5099-06 3
Table of Contents
Table of Contents Transmission, SPN 736 - FMI 3 ............................ 88

Transmission, SPN 736 - FMI 5 ............................ 89
Systems Operation Section Transmission, SPN 737 - FMI 5 ............................ 94
General Information ................................................ 4
Transmission Shifting Function ............................... 6
System Protection Functions ................................ 12
Additional Functions ............................................. 14
Transmission, SPN 739 - FMI 3 .......................... 101
Programmable Parameters ................................... 16
Transmission Control ........................................... 19
Electronic Control Unit .......................................... 23
Input Components ................................................ 27
Output Components .............................................. 31
Data Link .............................................................. 32
Transmission, SPN 744 - FMI 5 ........................... 111
Troubleshooting Section Transmission, SPN 744 - FMI 6 ........................... 114
Transmission, SPN 973 - FMI 9 ........................... 115
Introduction Transmission, SPN 973 - FMI 19 ......................... 117
General Information .............................................. 35 Transmission, SPN 1716 - FMI 8 ......................... 118
Service Tools ........................................................ 35 Transmission, SPN 1716 - FMI 13 ...................... 120
Connector Locations ............................................. 36 Transmission, SPN 3027 - FMI 3 ........................ 121
Diagnostic Capabilities ......................................... 39 Transmission, SPN 3027 - FMI 4 ........................ 122
Transmission, SPN 3463 - FMI 2 ........................ 125
Symptom Troubleshooting Transmission, SPN 3509 - FMI 3 ........................ 127
Engine Does Not Crank ........................................ 41 Transmission, SPN 3509 - FMI 4 ........................ 129
Transmission Does Not Automatically Shift Into Transmission, SPN 3823 - FMI 3 ........................ 130
Neutral ................................................................ 41 Transmission, SPN 3823 - FMI 4 ........................ 132
Transmission Does Not Automatically Shift Back Into Transmission, SPN 3823 - FMI 16 ...................... 133
Gear .................................................................... 41 Transmission, SPN 3824 - FMI 3 ........................ 135
Transmission Does Not Respond to Shift Transmission, SPN 3824 - FMI 5 ........................ 136
Selector ............................................................... 42 Transmission, SPN 3824 - FMI 6 ........................ 137
Replaced Relay or Solenoid Does Not Operate ... 42 Transmission, SPN 3825 - FMI 8 ........................ 139
Diagnostic Trouble Code Procedures
Diagnostic Trouble Code List ................................ 43
Testing and Adjusting Section
Determining Diagnostic Trouble Codes ................ 44
Testing and Adjusting
Transmission, SPN 91 - FMI 9 .............................. 48
Speed Sensor - Replace ..................................... 142
Transmission - Calibrate ..................................... 142
Electrical Connector - Inspect ............................. 144
Wiring Harness (Open Circuit) - Test .................. 148
Wiring Harness (Short Circuit) - Test .................. 149
Electronic Control Unit - Flash Program ............. 149
Electronic Control Unit - Configure ..................... 149
Electronic Control Unit - Replace ........................ 150
System Schematic .............................................. 151
Transmission, SPN 190 - FMI 8 ............................ 63 Index Section
Transmission, SPN 191 - FMI 14 .......................... 68 Index ................................................................... 158
4 KENR5099-06
Systems Operation Section

i03005395
General Information
SMCS Code: 4800
g01343860
Illustration 1
KENR5099-06 5
The Transmission ECU electronically interrelates with Transmission ECU

the following functions, sensors, inputs and outputs:
The ECU is located on the top left of the transmission.
• OEM Components The ECU has two connectors. The first connector is
for the Caterpillar transmission harness. the second
• Transmission Monitoring Lamps connector is for the vehicle OEM harness. The ECU
is controlled by software that is specifically developed
• Torque Converter Outlet Sensors by Caterpillar for this transmission.
• Transmission Sump Temperature Sensors Shift Selector
• Transmission Filter Bypass Switch The transmission shift selector is a J1939 device
on the data link that communicates the preferences
• Engine Speed Sensors of the operator to the Transmission ECU. The shift
selector has a display that indicates the current gear.
• Converter Output Sensors The display also functions as an indicator for tasks
that are related to service.
• Transmission Speed Sensors
Temperature Sensors
• Oil Level Sensor
The ECU monitors the temperature of the torque
• Transmission Shift Points converter oil at the outlet. The ECU also monitors the
temperature of the transmission oil in the sump.
• Neutral Start Function
Oil Level Sensor
• Parking Brake
The oil level sensor is used in order to check the
• Torque Limiting level of the oil in the transmission. The operator may
initiate this check with the controls that are on the
Not all of the components in the diagram are required shift selector. The ECU takes no action if the oil level
during basic vehicle operation. is low. The operator is responsible for initiating any
required maintenance. The check can be initiated
under the following conditions:
General Operation
The ECU provides the service technician with • The engine speed is at idle.
enhanced diagnostic capabilities. This is available
through the use of onboard memory. Onboard • The transmission is in Neutral.
memory stores the possible diagnostic trouble codes
for retrieval at the time of service. Service personnel • The vehicle is stationary.
should use the Caterpillar Electronic Technician (ET)
for troubleshooting. • The vehicle is level.
The following electronic control modules • Transmission at operating temperature

communicate with each other through the J1939
Speed Sensors
data link: Engine, Transmission, Anti-lock Brake,
and Traction Control Systems (if equipped). These
modules share internal information and may There are four speed sensors on the transmission.
The Transmission ECU uses four speed signals in
temporarily control other modules that are connected
order to control the performance of the transmission.
to the data link. Other devices connected to the
data link, such as an instrument cluster, can display The ECU also uses the four speed signals for
scheduling the shifts and in order to perform shifts.
information that is broadcast over the data link. Other
The speed sensors monitor the following:
devices may use the data link in order to broadcast
the positions of switches. The service brake and the
parking brake are examples of switch information • Engine speed
that can be based on the data link.
• Torque converter output shaft speeds
Overview • Dual transmission output shaft speeds
There are no sensor outputs that are accessible to
the customer. All sensor outputs are only available
over the J1939 or the J1587 data link.
6 KENR5099-06
Oil Filter Bypass Pressure Switch • Pressure sensors

The oil filter bypass pressure switch is a normally • Temperature sensors
closed switch. The switch activates when the oil filter
for the transmission becomes plugged and the filter Transmission Monitoring Lamps
can no longer provide proper filtration of the oil. Oil
bypasses the filter when the filter becomes plugged. The OEM is responsible for providing and installing
A lamp will illuminate in order to alert the operator lamps in order to indicate active diagnostic
of the condition. conditions. The ECU operates the lamps through a
low side electrical driver. The driver is capable of a
Solenoids that are controlled by the Transmission maximum of 300 mA. The circuits are not designed
to support components other than lamp circuits. The
The CX28 transmission uses five clutch solenoids. amber lamp is used in order to indicate a diagnostic
The CX31 transmission uses five clutch solenoids. condition that does not warrant an immediate danger
The CX35 transmission uses six clutch solenoids. to the transmission. The amber lamp is the “Check
The solenoids control oil flow to the actuator pistons. Transmission” lamp. The red lamp is used in order
The solenoids and the clutches are engaged in order to designate abnormal operating conditions that are
to provide the following: serious such as a plugged filter or an oil temperature
that is too high.
• Six operating gears on the CX28
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• Six operating gears on the CX31
Transmission Shifting
• Eight operating gears on the CX35
Function
• One reverse gear
SMCS Code: 4800
• Torque converter lockup clutch engagement
Auto Neutral Function
• Optional: Fail in gear
The auto neutral function is used to neutralize
• Optional: Retarder (CX31 & CX35 Only) the transmission when an external attachment is
activated. This function can be programmed to
Torque Limiting automatically shift back out of neutral if conditions
warrant or it may require the operator to reselect his
The transmission can limit the maximum torque direction again. There are a set of programmable
that may be transferred to the drive train. The parameters to activate the auto neutral functionality
transmission is provided with a default level of torque and tailor it to the application.
limiting. Also, there is some flexibility in programming
new limits. The auto neutral function parameter will essentially
disable the whole feature if programmed to OFF. The
Power Take-Off (PTO) auto neutral inputs will not affect the transmission
if this feature is programmed to OFF. The second
The power take-off feature set allows thorough control parameter, auto neutral switch type, defines the
of the vehicle PTO devices. Various configuration switch inputs used for the auto neutral function. The
modes are available for controlling the auxiliary and switch can be a single input SWC input, single input
driveline PTO functions. SWB, or a dual input SWC input.
Monitoring and Protection The following is the input for the single switch to
common:
The transmission monitors the function and
performance with the use of sensors and diagnostic
software. The Transmission ECU will enable one
or both of the two lamps connected to the vehicle
connector in the event of a diagnostic condition. Also,
one or more of the diagnostic trouble codes will be
displayed on the shift selector. The active diagnostic
trouble codes are broadcast over the J1939 data link.
The ECU monitors the following sensors:
• Output sensors
• Input sensors
KENR5099-06 7
Table 1 If the direction inhibit function is programmed to OFF,

Auto Neutral Switch Wiring Required it means the direction inhibit function is disabled. If the
Programming parameter is programmed to REV, the direction inhibit
SWC is enabled. When a shift to REVERSE is attempted
the transmission is locked to NEUTRAL. Locked
None No switch input required to NEUTRAL means that the operator must select
SWG (Switch to Sensor J2-40 NEUTRAL on the shift selector before attempting
Common) another shift to REVERSE. The shifter display will
show “RN”. If the parameter is programmed to FOR,
Dual SWG (Switch to J2-40 and J2-41 the direction inhibit is enabled. When a shift to a
Sensor Common)
forward gear is attempted the transmission is locked
Switch to Battery(1) J2-14 to NEUTRAL. Locked to NEUTRAL means that the
operator must select NEUTRAL on the shift selector
Switch to Battery(2)(3) J3-2
before attempting another shift to a forward gear. The
(1) Switch to Battery 1is unavailable if the Drive Line PTO is shifter display will show the maximum forward gear
“Enabled” available and an N “**N”. If the switch is programmed
(2) Not available for CX31 with “Fail In Gear” set to “Enabled”
(3) Not available for CX35
to FORWARD and REVERSE, then the direction
inhibit will not allow any shift to a forward gear or
reverse. Once the direction has been attained, then
The following is the input for the switch to battery. the input does not affect the direction selection. When
Table 2
the direction inhibit is enabled by the switch, the
switch is in the open position. Once a directional shift
Auto Neutral Input Auto Neutral State has been prohibited, you must select Neutral with the
SWB shifter, put the switch in the closed position, and then
+BATT Disabled reselect the desired gear. The transmission will not
allow a shift to gear until this has been completed.
Open Enabled
Note: If the switch is opened and the direction inhibit
is enabled while the transmissin is in gear, the
Direction Shift Inhibit Function transmission will remain in the active gear. Once the
transmission is shifted in to Neutral by selecting “N”
Direction Shift Inhibit is implemented via J1939 for on the shifter, any attempt to shift in to a gear that is
use with on-highway truck engines. The directional selected for inhibit will be prohibited.
shift management function is used to reduce driveline
stress during directional shifts. The Transmission The function is configurable using the Cat ET service
ECU sends a signal to the engine ECU during tool. The direction inhibit switch type parameter is
directional shifts. This signal is used in order to used to specify whether a single switch SWC type
reduce torque during a shift. Cycle the keyswitch in input or one of the SWB type inputs is used.
order to activate the feature after the paramter has
been selected. Table 3
Direction Inhibit #1 Direction Inhibit State
SWC
Ground Direction shift enabled
Open Direction shift disabled
Table 4
Direction Inhibit Single Direction Inhibit State
SWB
+BATT Direction shift enabled
Open Direction shift disabled
8 KENR5099-06
Driveline PTO Mode Driveline PTO Inertia Brake - The Driveline PTO
feature includes a mode where, if the NEUTRAL
The Driveline Power Take-Out (PTO) feature is selected while the parking brake is set and the
allows the transmission to provide mechanical driveline PTO Engagement request switch is ON,
power through the transmission output shaft for the transmission will apply an internal brake to stop
non-propulsion purposes. The Driveline PTO the output shaft speed rotation if the engine, and
feature is used to provide mechanical power to transmission output shaft speeds are initially less
non-propulsion vehicle components, such as pumps than 1000 rpm.
or generators. The feature provides modified
gear selection, torque converter lockup clutch Driveline PTO Engaged Input - This input indicates
engagement, and a configurable output shaft brake that the DPTO driven equipment is mechanically
feature. This customer parameter is used to enable engaged to the transmission output shaft. This
the feature, and program which transmission gear input, in conjunction with the Driveline PTO Request
will be used during Driveline PTO operation. The input, results in the transmission selecting the gear
Driveline PTO feature requires the following switch indicated in the Driveline PTO Mode Enabled Gear
inputs: Configuration parameter when the operator selects
the drive range (“D” button) on the operator shifter
• Park Brake interface.
• DPTO Request DPTO and Parking Brake Interaction - The

Driveline PTO functionality requires the parking brake
• DPTO Latch Enable operation so it should be programmed to ON and the
wiring to the parking brake pressure switch circuit
Driveline PTO Mode Enable Gear Configuration installed. The programmed state ON w/Neutralize
- The DPTO Mode Enabled Gear Configuration means that the parking brake will be read, but it will
parameter provides the ability to choose the desired also neutralize the transmission when it is set. The
gear for DPTO operation. When the feature is transmission is put in NEUTRAL if the output speed is
programmed to Disabled, the feature will not function. below the programmed value, the shift selector is not
in NEUTRAL, and the parking brake input is set. The
Driveline PTO Latching Engine Speed - Some transmission is held in NEUTRAL until the operator
applications require the Driveline PTO (DPTO) shifts to NEUTRAL and then back to a range. The
mode to be disengaged solely based on the engine transmission will remain in gear until the operator
speed value. This provides a robust system, shifts into NEUTRAL or releases then re-applies the
which once the DPTO is engaged, will continue to parking brake.
function during vehicle electrical faults. A customer
parameter is provided to set the engine speed that Lockup Clutch Function
will “latch” the DPTO mode. Caution should be used
in implementing a Driveline PTO Latching speed, in The lockup clutch controls the direct drive electrically.
that the only method of neutralizing the transmission When the ECU activates the lockup solenoid the
is to reduce the engine speed to less than the lockup clutch in the torque converter mechanically
programmed parameter value. Interrupting electrical connects the torque converter input shaft to the
power to the transmission, selecting NEUTRAL from torque converter output shaft. This mechanically
the shift selector interface, changing the status of connects the transmission to the engine.
the Driveline PTO switch input to the transmission
control, or releasing the parking brake will not ensure The ECU keeps the lockup clutch engaged as much
the transmission will select a neutral gear. as possible during normal operation. When the
transmission shifts the lockup solenoid is deactivated
Driveline PTO Torque Converter Lockup Clutch for easier shifting. The vehicle is in torque converter
Engagement Speed - The transmission torque drive when the lockup solenoid is deactivated.
converter clutch may be engaged during DPTO
operation, to increase the efficiency of the overall The transmission's reverse gear and the
vehicle system. The torque converter lockup clutch transmission's neutral gear are torque converter
may remain disengaged to provide a compliant drive. First gear is torque converter drive. The second
element in the DPTO system if required. The gear is torque converter drive on the low end and
transmission once the initial DPTO range is attained, direct drive on the high end. The third gear and all
will engage the torque converter lockup clutch when other forward transmission gears are direct drive.
the PTO LUC Engagement Speed is exceeded, after Direct drive means that the transmission output shaft
a short (- 1 second) delay time is reached. Once is mechanically connected to the input shaft.
engaged, the torque converter lockup clutch will
disengage when the engine speed is 200 rpm less
than the programmed speed, or if the engine falls
below low idle speed.
KENR5099-06 9
First Gear and Torque Converter Lock Up If the neutral to gear inhibit function is programmed
Function to OFF, it means the direction inhibit function is
disabled. If the parameter is programmed to REV,
Some vehicle operations require that the torque the direction inhibit is enabled. When a shift to
converter's lock up clutch be engaged when the REVERSE is attempted the transmission is locked
transmission is in the first gear forward. A typical to NEUTRAL. Locked to NEUTRAL means that the
operation example would be operation on a steep operator must select NEUTRAL on the shift selector
down hill grade that requires engine retarding at before attempting another shift to REVERSE. The
slow vehicle speeds. Another example includes shifter display will show “RN”. If the parameter is
preventing transmission oil temperature increases programmed to FOR, the direction inhibit is enabled.
when operating for extended periods of thime while When a shift to a forward gear is attempted the
in the first gear forward in torque converter drive. The transmission is locked to NEUTRAL. Locked to
torque converter's lock up clutch will engage when NEUTRAL means that the operator must select
first gear is the programmed maximum desired gear NEUTRAL on the shift selector before attempting
and the engine speed is more than 1400 rpm. The another shift to a forward gear. The shifter display will
lock up clutch will disengage when the engine speed show the maximum forward gear available and an N
is below 1400 rpm. “**N”. If the switch is programmed to FORWARD and
REVERSE, then the neutral to gear inhibit will not
The maximum desired gear of the vehicle is allow any shift to a forward gear or reverse. Once
controlled by the operator by using the down arrow the shift has been attained, the input does not affect
button on the shift pad to the first gear position. The the gear selection. When the neutral to gear inhibit
maximum desired gear can also be controled by is enabled by the switch, the switch is in the open
moving the shift lever to the first gear position. position. Once a shift has been prohibited, you must
select Neutral with the shifter, put the switch in the
Note: If the operating conditions require the closed position, and then reselect the desired gear.
transmission to upshift to the second gear, the lock The transmission will not allow a shift to gear until
up clutch will disengage in order to prevent an engine this has been completed.
over speed event.
If the switch is opened and the neutral to gear inhibit
is enabled while the transmissin is in gear, the
Neutral To Gear Inhibit Function transmission will remain in the active gear. Once the
transmission is shifted in to Neutral by selecting “N”
The neutral to gear inhibit function provides the on the shifter, any attempt to shift in to a gear that is
ability for inhibiting shifts out of NEUTRAL due to selected for inhibit will be prohibited.
external equipment of the vehicle in operation. This
function requires a switch input and programmable Table 5
parameters through the service tool. If this function is
Neutral to Gear Input Neutral to Gear State
enabled via the programmable parameter, then the SWC
function must be integrated in the vehicle wiring. This
input can be used in order to prevent unwanted shifts Ground Disabled - allow shifts from
out of neutral when external equipment is operating neutral
or other vehicle functions such as a seat switch. Open Enabled - no shifts from
Cycle the keyswitch in order to activate the feature neutral
after the paramter has been selected.
Table 6
Neutral to Gear Input Neutral to Gear State
SWB
+BATT Disabled - allow shifts from
neutral
Open Enabled - no shifts from
neutral
10 KENR5099-06
Top Gear Function When the engine retarder is on, the upshift and
downshift points are raised because the retarder
This feature is defaulted to “ON”, but can be systems are more effective at higher engine speeds.
configured to either “ON” or “OFF” using Cat ET. This
function limits the maximum ground speed of the Transmission PTO Control
vehicle. The ECU prevents upshifting to any gear
that is greater than top gear. The value for top gear Selection
is stored in the ECU. The value of the top gear is
programmable by the service personnel. The value The transmission PTO feature controls the PTO
of the top gear is programmed at the factory to the enable output driver at J2-6. The PTO enable driver
maximum top gear for the particular vehicle model. is used to control an OEM supplied control system
that is connected to the transmission's auxiliary
Note: The Cat ET service tool can be used to output shaft. This output is capable of driving 2 Amps
program the top gear function. Use the configuration and will be turned ON when all of the programmed
screen in the Cat ET service tool in order to change conditions have been met.
the top gear setting.
This function requires a SWC input, an Output
The range of numbers for the CX28 are listed below. Driver, and a set of programmable parameters that
are controlled by the service tool. The PTO Control
Factory setting .................................................. 6 function reads an operator PTO switch input in order
Range ........................................................ 3 to 6 to direct it to turn on the PTO driver.
The range of numbers for the CX31 are listed below. Each system has specific operational conditions that
must be met. The operational conditions are set by
Factory setting .................................................. 6 accessing the programmable parameters with the
Range ........................................................ 3 to 6 service tool.
The range of numbers for the CX35 are listed below. The following items are available for tailoring the
Factory setting .................................................. 8 PTO operation for a specific vehicle:
Range ........................................................ 1 to 8
PTO Mode Enable - The PTO mode enable
parameter must be programmed to enabled before
Alternate Maximum Gear Function any of the other parameters will be in effect.
This function allows for customization of the PTO Mode Neutral Restriction - The PTO neutral
maximum gear in the alternate shift schedules. The restriction parameter is used to restrict the PTO
default setting is Disabled. Any available gear may operation to NEUTRAL. The PTO “ON/OFF” switch
be selected as the maximum gear.The shift selector status will be ignored when the transmission is not in
reflects the programmed value on the left of the NEUTRAL.
gear display when the alternate shift schedule is
active. The transmission will limit operation to the PTO Mode Gear Limit - The PTO mode gear limit
programmed gear unless an upshift is required in parameter is used to limit the maximum gear that
order to prevent an engine over speed event. the PTO enable output may be energized. When
programmed to FIRST gear, then the PTO enable
Rapid Downshift Function output may be energized when in NEUTRAL,
REVERSE, or FIRST gear. The PTO operation will
The ECU does not allow a turnaround shift until a be blocked the transmission is in SECOND gear or
short time after a shift occurs. A turnaround shift is an a higher gear.
opposite shift from the previous shift. For example,
a downshift is prevented for a short time after an PTO Mode Maximum Engine Speed for
upshift and an upshift is prevented for a short time Engagement - The PTO enable output can be
after a downshift. The turnaround feature allows the restricted from energizing at too high of an engine
conditions to stabilize before an opposite shift. The RPM.
delay prevents hunting between gears.
PTO Mode Maximum Engine Speed for Operation
- This feature limits the PTO operation to below the
Elevated Downshift Function programmed engine RPM. When the engine rises
above the programmed limit the PTO enable output
This function improves retarding performance by will de-energize.
elevating the upshift and the downshift points. When
the retarder on the service brake is engaged, the
ECU raises the shift points.
KENR5099-06 11
PTO Mode Maximum Engine Speed for Hold Input Function

Engagement - This feature is used in order to
prevent the PTO enable output from energizing This function requires a SWC input and a
above the programmed RPM. programmable parameter through the service tool.
When the hold input is set, the transmission will
PTO Maximum Engine Speed for Operation - This attempt to hold the current gear. The transmission will
feature is used to limit the PTO operation to below the only upshift at the engine over speed point. Normal
programmed transmission output shaft speed. When downshifting is allowed as the vehicle slows down.
the output shaft speed rises above the programmed As the transmission downshifts, the hold continues
limit, the PTO enable output will be de-energized. which means that the transmission will stay in the
downshifted gear unless the engine over speed point
Shifter Selection Function allows it to upshift again.
Table 7
The ability to have two shift selectors is desired
for some applications. This function requires a Hold Input Programming Function Input
SWC input to the ECU sensor common and some Disabled N/A
programmable parameters.
SWG J2-55
Note: The SWC must return to pin J2-22 for sensor J1939 Shifter Mode Button
common at the ECU. A chassis ground connection
for the SWC is incorrect.
OFF means the input is disabled. ON means the
When the shift selector input has a closed circuit, input and function are enabled. The hold input can be
then the shift selector input switches to the second a SWC input or the Mode Button on the shift selector.
shift selector. The switch will only occur if both shift The hold input button is a momentary switch when
selectors are selecting NEUTRAL, the transmission used with a SWC input.
is in NEUTRAL, and the output speed is zero. The
display of the inactive shift selector is blank if it is a If the transmission is in a forward range and the
push button shift selector. If any of the conditions are “MODE” button is pressed and released, the hold
not met, then the shift selector input will not switch function is active and the current selected gear is the
until all the conditions are met. gear to attempt to hold. If the operator presses and
releases the “MODE” button again, then the function
The secondary shifter parameter is used to designate is disabled. If a different range is selected, the hold
whether or not a secondary shifter is installed. When function is disabled. Selecting a different range can
the paramter is programmed to “Not Installed”, the be done by choosing NEUTRAL or by pushing the up
transmission will ignore the switch input at contact or down buttons on the shift selector.
J2-35. The the parameter is programmed to “J1939”,
the transmission will respond to the secondary shifter Quick Gear Limit
when the circuit is closed at contact J2-35.
The Quick Gear Limit feature is used to limit the
Note: When the secondary shifter is installed, the transmission gear selection to a customer-specified
display will show the active gear selection of the level, when OEM installed inputs to the transmission
transmission. control indicate gear-limited transmission operation
is desired. The Quick Gear Limit Feature utilizes an
Economy Shift Mode OEM installed switch circuit or shift selector MODE
switch activation to indicate that the transmission
This function is a SWC input or switch via the Mode will not upshift beyond 1st gear. This feature can be
switch on the shift selector. The economy mode is used to effectively limit vehicle speed during vehicle
used to lower the full throttle shift points. This mode maneuvering or stop-and-go driving during refuse
is typically used for lightly loaded vehicles in urban applications. Further, the reverse range may be
environments. OFF means the input is disabled. On inhibited during Quick Gear Limiting if desired. The
means the input is enabled. If the SWC input has a Quick Gear Limit feature only inhibits upshifts past
closed circuit, then the transmission control has the 1st gear. If the transmission is above 2nd gear, the
economy mode active. When the “MODE” button is transmission will continue to operate normally until
used to activate the feature, the “MODE” button LED 2nd gear is attained, at which time upshift will normally
will be enabled. The LED will remain enabled as long be inhibited. Vehicle operation conditions sufficient
as the feature is active. to over speed the engine in 1st gear will result in an
engine-protection upshift to higher gears.
Quick Gear Limit Function Customer Parameter

Programming -
12 KENR5099-06
Programming as shown enables the Quick Gear When the key switch ON input turns OFF, the
Limit function: transmission software will continue to run normally
until one of the following two conditions are met :
Quick Gear Limit Switch Customer Parameter
Programming - The quick Gear Limit switch may be 1. The transmission output speed is zero and the
programmed to any one of 4 inputs. Three switch to transmission is the NEUTRAL position.
battery positive, and one switch to sensor common
inputs are available. 2. The transmission output speed is zero and the
engine speed is zero.
Table 8
Input Contact Description The second statement covers the event of the shift
selector being left in gear or is faulted because it
J2/P2:35 Switch to sensor common shuts down due to power being turned off. When the
input for the Quick Gear shift selector is faulted, the shift control logic holds
Limit function.
the previous position of the shift selector and will
J2/P2:14 Switch to battery input not shift to NEUTRAL as long as the shift selector is
for the Quick Gear Limit faulted and was previously in a gear.
function.
J3/P3:2 Switch to battery input Transmission Filter Bypass
for the Quick Gear Limit
function. Function
J3/P3:5 Switch to battery input The transmission filter bypass function is used in
for the Quick Gear Limit order to warn the operator when the transmission
function. filter is being bypassed. The filter could be plugged
due to contamination. The red warning lamp indicator
Quick Gear Limit Input-Switch to Battery - is turned ON in order to warn the operator.
The Quick Gear Limit Input may be configured
as a switch-to-battery input, using any of the 3 The filter bypass input is a switch to common. If
switch-to-battery inputs available on the transmission this input has a closed circuit, then the filter is not
control. bypassing (OK). If the input has an open circuit,
then the filter is bypassing (PLUGGED). A warning
Quick Gear Limit Input-Switch to Common - The will occur if the input wire to the ECU breaks. If the
Quick Gear Limit Input is configured as a switch to oil is not bypassing and an open circuit exists, then
common. the harness needs to be checked and repaired.
When the transmission filter bypass input indicates
Quick Gear Limit Logic - The Quick Gear Limit that the filter is plugged, an event is logged and the
feature only limits the transmission-selected gear transmission warning lamp is activated.
to 1st forward, or 1st forward and 1st reverse. If the
transmission is in 3rd or higher gear when the Quick Starter Interlock Output Function
Gear Limit Switch is ON, the transmission will not
take any actions to effect the shift points. IF the The starter inhibit parameter is used in order to
transmission is in 2nd gear or lower, the transmission prevent the engagement of the engine starter motor
will inhibit upshifts until the Quick Gear Limit switch is while the engine is running. This feature is typically
OFF. enabled on rear engine applications, where the
operator cannot sense that the engine is running and
i02801528 attempts to start the engine. The parameter controls
the output at J2-7. When programmed to enabled,
System Protection Functions the starter interlock will be enabled when the starter
input is in the ON position, the transmission is in
SMCS Code: 4800 NEUTRAL, and the engine speed is 100 RPM below
the low idle point that is specified in the J1939 Engine
Power Down Function Configuration message. If the Engine configuration
message is not received, then the output is disabled
The Transmission ECU will have the ECU positive at 550 RPM. When programmed to disabled, the
voltage lines of the battery run to unswitched battery starter interlock will be enabled when the engine start
in the vehicle harness. The key switch ON (J3-7 to input is connected to the battery.
J1-1) pin on the Transmission ECU is run to the key
switch ON position in the vehicle and when it turns
off, the software controls when the Transmission
ECU actually shuts down.
KENR5099-06 13
Engine Overspeed Protection Warning Lamp

When the engine speed increases to a predetermined The warning lamp turns on when there is a
level, the Transmission ECU will upshift. The transmission overtemp event or transmission filter
transmission will shift ONE gear position past the bypass event. This is for the red transmission warning
operator's selection in order to protect the engine lamp in the dash. The lamp turns on at a specific
from overspeed. torque converter temperature and turns off at a lower
temperature. The temperature set points for this
feature can be programmed to the following values:
Torque Limiting Function
A factory password protected programmable • Torque Converter High Temperature Turn On :
151 °C (304 °F)
parameter with a programmable range of 8000-65000
N·m. This configurable parameter is used to limit
engine torque to protect driveline components. • Torque Converter High Temperature Turn Off :
142 °C (287 °F)
This value reflects significant margin on the
most aggressive torque converter match for
on-highway applications. The customer parameter is • Transmission Sump High Temperature Turn On
: 121 °C (250 °F)
programmable with Cat ET.
• Transmission Sump High Temperature Turn Off :
Directional Shift Management 113 °C (235 °F)
Function
Speed Enable Output
The Transmission ECU will not allow a directional
change if the engine speed is above 1000 rpm or The speed enable output is an output driver that
transmission output speed is above 150 rpm. If either turns ON when the engine exceeds the programmed
of these conditions are not met when the operator engine speed or output speed value. The output
commands a directional shift, then the transmission turns off when the engine speed goes below a
will shift to NEUTRAL and the desired gear display programmed speed value. This output can be used to
will flash. The operator will then have to select turn on a lamp when a specific output speed is being
NEUTRAL before selecting FORWARD or REVERSE exceeded or to enable some vehicle functionality
after this has occurred. when a specific engine speed or output speed is
reached. This output requires some programming to
Tattletale Function enable it and to set the turn on and off speeds.
Tattletales are incremented by one when a parameter The programmable parameters would be as follows:
value is changed by using the Cat ET. The number is
displayed on the right of the Cat ET screen. • Speed Enable Output: OFF/Engine Speed/Output
Speed/PTO Engine Speed
This function is a tool that is used as an aid for
managers and maintenance personnel. This function • Speed Enable Turn On RPM: 0-5000 rpm default:
allows tracking of the parameter value change history 5000
of the vehicle.
• Speed Enable Turn Off RPM: 0-5000 rpm default:
5000
Check Transmission Lamp
The speed enable output will not change state if the
The check transmission lamp function turns on when programmable parameter is programmed to OFF. If
there is a diagnostic that is active. This lamp is an it is programmed to “Engine Speed”, then the output
amber colored lamp. turns on when engine speed exceeds the “Speed
Enable turn On RPM” programmed value. It will turn
Note: The check transmission lamp driver output will off when the engine speed is below the programmed
turn on for five seconds at power up, then turn off for “Speed Enable turn Off RPM” value. If the “Speed
0.5 seconds before going to normal mode. This is for Enable Output” parameter is programmed to “Output
a bulb check on power up of the system. Speed”, then output speed is used to turn on and
off the speed enable output. If the “Speed Enable
Output” is programmed to “PTO Engine Speed”, then
the output is turned on when engine speed exceeds
the “Turn On RPM” and the “Transmission PTO”
mode is active. If the “Transmission PTO” mode is
not active, then the “Speed Enable Output” will not
turn on under this programmed mode.
14 KENR5099-06
Fan Control for High Transmission If the starter interlock output is currently disabled,
then the output conditions for the function to be
Oil Temperature enabled are ON if the transmission shift selector is
in Neutral, the transmission is actually in Neutral,
There are warnings when the torque converter oil
and the engine speed signal is 0 RPM. If the starter
temperature reaches a set value. The on-highway
interlock output is currently enabled, then the output
engine electronic control usually controls the fan on
conditions for the function to be disabled are if the
the truck, but it is not looking at the transmission
shift selector is moved from neutral, the actual gear
oil temperature. But, via the J1939 data link, the
is not neutral, or the engine speed signal has gone
transmission can send a message to turn on the
above (low idle rpm – 100 rpm) for 0.5 seconds.
engine fan. The Transmission ECU will request
the fan to turn on when the torque converter oil
Note: The driver has the ability to drive up to 2 amps.
temperature or transmission sump oil temperature
goes above the turn on value and then turn off
when both torque converter temperature and Service Brake Operation
transmission sump oil temperature go below the turn
off temperature. The service brake operation is a function to read a
switch input or brake switch over the data link. The
• Fan Turn On Oil Temp: 129 °C (264 °F) engine control may already have a brake switch
input for cruise control, so the transmission control
• Fan Turn Off Oil Temp: 121 °C (250 °F) can use the information that is broadcast over the
data link. If the engine control does not have a
brake switch attached, then attach a brake switch
i02590501
to the transmission control directly. The service
Additional Functions brake information is used in order to enable certain
functions and is needed by the transmission control.
SMCS Code: 4800
Parking Brake
Backup Alarm Driver Output The parking brake can be disabled or enabled using
Function the ET service tool. The SWC input for the parking
brake input shows the parking brake set when
The backup alarm is used in order to alert any the input is a closed circuit. The parking brake is
personnel that is near the vehicle that the vehicle is disengaged when the input has an open circuit.
in the Reverse range. When the operator selects
REVERSE the ECU activates the relay for the backup The programmable parameters for the park brake
alarm which causes the alarm to sound. have the following selections:
The feature can be used in order to disable vehicle • Installed

systems. Such as steerable lift axles when the
transmission is in Reverse. Similarly, the feature can • Installed and Neutralizer Logic is Enabled
be used in order to enable backup alarms or lights.
This feature is not standard but recommended. • Not Installed
Note: The driver has the ability to drive up to 2 amps.
Starter Interlock Driver Output

Function
The starter interlock function is an output signal to
ensure conditions are met for the engine starter to be
engaged. The vehicle needs to ensure that the shift
selector is in neutral before allowing the engine to
start and that the engine rpm is 0.
KENR5099-06 15
When the parking brake option “Installed and Gear Driver Output Indicator
Neutralizer Logic is Enabled”is selected, the parking
brake can be used to prevent the vehicle operator The gear output indicator function is an on/off driver
from shifting into a range from Neutral without that will engage when specific gears are selected.
additional operator interaction. Transitioning the The gears that turn on the gear indicator are selected
Parking Brake control from OFF to ON after the by programmable parameters. The indicator can
vehicle has come to a complete stop (zero output be programmed to turn on for a single gear or any
shaft speed and zero vehicle speed broadcast over combination of gears.
the J1939 Data Link), the transmission will shift
into Neutral. Once in Neutral, the shift selector will There is a set of programmable parameters that have
indicate Neutral and the Desired Gear, Left “N” to be turned on for each gear that is desired to turn
on the shift pad, will flash. This indicates to the on this output:
operator that Neutral must be re-selected in order
for the transmission to shift into a desired range. • Gear Indicator Reverse - OFF/ON
The transmission will not automatically shift back
into the previous range. The operator is required • Gear Indication Neutral - OFF/ON
to select Neutral and then the desired range. The
operator can then drive through the Parking Brake if • Gear Indicator 1F - OFF/ON
desired. Once the operator selects Neutral and then
a range, the Neutralization feature is overridden. The • Gear Indicator 2F - OFF/ON
transmission will not automatically shift back in to
Neutral until the Parking Brake is released and then • Gear Indicator 3F - OFF/ON
reapplied with zero vehicle speed.
• Gear Indicator 4F - OFF/ON
Shift Selection Function
• Gear Indicator 5F - OFF/ON
The OEM transmission has one type of shift selector.
The shift selector is a push button shifter. The ability • Gear Indicator 6F - OFF/ON
to have two shift selectors is desired for some
applications. This function requires a SWC input to • Gear Indicator 7F - OFF/ON
the ECU sensor common and some programmable
parameters. The secondary shift selector input can • Gear Indicator 8F - OFF/ON
be a push button shifter.
Note: The driver has the ability to drive up to 300
Note: The SWC must return to pin J2-22 for sensor milliamps.
common at the ECU. A chassis ground connection
for the SWC is incorrect. Retarder
When the shift selector input has a closed circuit, When the engine retarder or the transmission
then the shift selector input switches to the second retarder is enabled, the transmission will raise
shift selector. The switch will only occur if both shift the downshift points automatically. Programmable
selectors are selecting NEUTRAL, the transmission parameters are available for controlling the response
is in NEUTRAL, and the output speed is zero. The of the transmission to the retarder engagement.
display of the inactive shift selector is blank if it is a The programmable parameters are available for the
push button shift selector. If any of the conditions are operator control of the transmission retarding levels.
not met, then the shift selector input will not switch The transmission retarder will only be enabled if the
until all the conditions are met. torque converter is locked up, the throttle is released,
and the engine speed is 200 rpm above the low idle
Shift Display Blank Input Function engine speed.
The shift display blank input function is where the Retarder Top Gear Limit Configuration
vehicle maker can add a switch for the operator to
turn off the shift selector display. There is a customer The configuration controls the highest gear that the
parameter to enable this feature and also a switch transmission will operate in while the retarder for the
selection to choose which input to use for this transmission or engine is engaged. Programming the
function. The function works if the input has a closed parameter to the highest gear disables the feature.
circuit, then the display is blanked. For the switch to The gear limit is not active unless a retarder is
battery type input, the display is blanked when the engaged and in the “high” mode.
input is tied to battery voltage.
16 KENR5099-06
Retarder Shift Enable Switch Alternate Start In Gear Driver

When a retarder is engaged the transmission will
Output
aggressively downshift to the programmed top
The function is used to choose the lowest gear
gear limit. The retarder shift enable switch allows
for transmission operation. When programmed to
for an operator to control how aggressively the
Disabled, the transmission will shift from Neutral to
transmission will downshift. With the switch closed,
the first forward gear when “D” is selected on the
the transmission will ignore the programming of the
shift pad. When programmed to Enabled and the
top gear limit and downshift normally.
dedicated switch inputs are closed, the transmission
will shift into second gear as the lowest range for
Retarder Gear Limit Brake operation. A lamp is enabled when the switch is
closed in order to inform the operator the Alternate
The parameter provides the option of requiring the Start Gear is enabled. The transmission will default
service brake to be applied before The transmission to the first gear if the switch is open. The lamp is
enables the top gear limit. disabled when the switch is open.
Note: If the retarder enable switch is closed, the top Note: The driver has the ability to drive up to 300
gear limit will still be disabled when the feature is milliamps.
“Enabled” and the service brake is applied.
Retarder Dual Switch

Fail In Gear
This feature is a factory ordered option that causes
With the transmission retarder switch programmed the transmission to fail in a forward gear. If power to
to Dual Switch to Sensor Common, the level of the ECU is removed while the vehicle is in operation,
transmission retarding may be controlled with the the ECU will latch into a gear. This is also referred
switch inputs. The allowable levels are Off, Low, to as “Limp Home”. The fail in gear hardware may
Medium, and High. be added to an existing transmission. However, an
authorized technician is required in order to enable
Note: If a switch is not programmed, the retarder will the feature with Cat ET. Enabling the feature will
be engaged at the highest level of retarding when result in the loss of a switch to battery 2 connection
the retarder is engaged. on the CX31 Transmission. The fail in gear solenoid
Table 9
allows the transmission to function normally when
the solenoid is receiving voltage.
Level Medium/High Low/High
J2-38 to J2-22 J2-42 to J2-22 Note: In the event that the machine is under normal
Off Open Circuit Open Circuit operation and the solenoid is disconnected or fails,
the transmission will not be allowed to shift to
Low Open Circuit Closed Circuit NEUTRAL. The shifter will show the desire to shift to
Medium Closed Circuit Open Circuit NEUTRAL, while the transmission remains in gear.
High Closed Circuit Closed Circuit
i02728856
Retarder Mode Programmable Parameters

The mode determines the operation of the SMCS Code: 4800
transmission retarder while the cruise control switch
is in the ON position but the engine is not in cruise Note: For an updated selection of the programmable
control. The feature does not determine or allow parameters, refer to Special Instruction, REHS2884,
transmission retarding while the engine is in cruise “Application and Installation Guide”.
control. The allowable options are “Coast”, “Latch”,
or “Manual”. When programmed to “Coast”, the
transmission retarder is enabled only while the
service brakes are applied. When programmed
to “Latch”, the transmission retarder will turn ON
when the service brakes are applied, but it remains
enabled after the service brakes have been released.
The retarder remains ON until the accelerator pedal
is depressed or some other condition disables the
transmission retarder.
KENR5099-06 17
Table 10
Parameter Available Range/Options Default
Equipment Identification Parameters

Engine Serial Number 18 characters Not Programmed
Vehicle ID 18 characters Not Programmed
Transmission Serial Number N/A Factory Programmed
Torque Converter Serial Number N/A Factory Programmed
Transmission PTO Configuration Parameters
PTO Neutral Restriction Disabled, Enabled Disabled
PTO Mode Enable Status Disabled or Enabled Disabled
Not Configured, Gear 1, Gear 2, Gear 3,
PTO Mode Gear Limit Not Configured
Gear 4, Gear 5, Gear 6, Gear 7, Gear 8
PTO Mode Maximum Engine Speed
0 - 5000 RPM 0
For Engagement
PTO Mode Maximum Engine Speed
600 - 3500 RPM 0
For Operation
PTO Mode Maximum Transmission
0 - 8000 RPM 0
Output Speed For Engagement
PTO Mode Maximum Transmission
0 - 8000 RPM 0
Output Speed for Operation
Driveline PTO Configuration Parameters
Driveline PTO Minimum Engine
500 - 3000 RPM 0
Speed for Latching
Driveline PTO Minimum Engine Speed
600 - 3000 RPM 1000
for Torque Converter Lockup
Driveline PTO Latching Enabled Status Disabled, Enabled Disabled
Driveline PTO Inertia Brake
Enabled, Disabled Enabled
Enabled Status
Driveline PTO Mode Enabled Gear Disabled, Gear 1, Gear 2, Gear 3, Gear
Disabled
Configuration 4, Gear 5, Gear 6, Gear 7, Gear 8
Vehicle Configuration Parameters
Governed Engine Speed 1800 - 3500 RPM 2100
Peak Torque Engine Speed 1000 - 2500 RPM 1200
Transmission Output Shaft Torque
0 - 48336 lb-ft 48336
Limit Configuration
Auto Neutral Function Enabled Status Disabled, Enabled Disabled
Auto Neutral Gear Reengagement
Not Required, Required Not Required
Brake Required Configuration
Disabled, Enabled for Forward,
Auto Neutral Gear Reengagement
Enabled for Forward and Reverse, Disabled
Configuration
Enabled for Reverse
Maximum Transmission Output Speed
0 - 8000 RPM 0
to Enable Auto Neutral
Installed, Installed and Neutralizer
Parking Brake Input Installation Status Installed
Logic is Enabled, Not Installed
(continued)
18 KENR5099-06
(Table 10, contd)

Neutral to Gear Inhibit Function
Enabled for Forward and Reverse, Disabled
Configuration
Enabled for Reverse
Direction Inhibit Function Configuration Enabled for Forward and Reverse, Disabled
Enabled for Reverse
Disabled, Enable to First Gear and Do
Quick First Gear Limit Configuration not lock out Reverse, Enabled to First Disabled
Gear and Inhibit Shifts to Reverse
Transmission Fail In Gear Enabled
Disabled, Enabled Disabled
Status
J1939, Not Installed, (PWM-Not
Shifter #1 Configuration J1939
Supported)
J1939, Not Installed, (PWM-Not
Shifter #2 Configuration Not Installed
Supported)
Selected System Voltage 12, 24 Volts 0
Transmission Default Shift Schedule Economy 1, Economy 2, Performance
Performance 1
Configuration 1, Performance 2
Transmission Default Maximum Disabled, Gear 1, Gear 2, Gear 3, Gear
Disabled
Gear Configuration 4, Gear 5, Gear 6, Gear 7, Gear 8
Transmission Alternate Shift Schedule Economy 1, Economy 2, Performance
Economy 1
Configuration 1, Performance 2
Transmission Alternate Maximum Disabled, Gear 1, Gear 2, Gear 3, Gear
Disabled
Gear Configuration 4, Gear 5, Gear 6, Gear 7, Gear 8
Minimum Start Gear Configuration Gear 1, Gear 2 Gear 1
Transmission Calibration Configuration Disabled, All Clutches All Clutches
Retarder Configuration Parameters
Disabled, Gear 1, Gear 2, Gear 3, Gear
Retarder Top Gear Limit Configuration Disabled
4, Gear 5, Gear 6, Gear 7, Gear 8
Retarder Gear Limit Brake Input
Disabled, Enabled Disabled
Enabled Status
Transmission Retarder Installation
Not Installed, Installed Not Installed
Status
Input Selections
J1939 Body Controller, J1939
Service Brake Input Configuration Cab Controller, J1939 Instrument J1939
Cluster, Switch Input
J1939 Body Controller, J1939 Cab
Parking Brake Input Configuration Controller, J1939 Instrument Cluster, Switch to Ground
Not Configured, Switch to Ground
J1939, Not Configured, Switch
Economy Mode Input Configuration Not Configured
to Ground
Disabled, Gear 1, Gear 2, Gear 3, Gear
Blank Shift Display Configuration Disabled
4, Gear 5, Gear 6, Gear 7, Gear 8
Minimum Forward Start Gear Input
Mode Button Input, Switch Input Switch to Ground
Configuration (CX35 Only)
(continued)
KENR5099-06 19
(Table 10, contd)
Not Configured, Mode Button Input,

Quick Gear Limit Switch Configuration Switch to Battery 1, Switch to Battery 2, Not Configured
Switch to Battery 3, Switch to Ground
Hold Function Input Configuration Disabled, J1939, Switch to Ground Disabled
Dual Switch Input, J1939 Body
Transmission Retarder Input
Controller, J1939 Cab Controller, J1939 PWM
Configuration
Instrument Cluster, PWM
Output Selections
Engine Running Starter Inhibit
Disabled, Enabled Enabled
Enable Status
Disabled, Engine Speed, PTO Engine
Speed Enabled Output Configuration Disabled
Speed, Transmission Output Speed
Speed Enabled output Turn On Speed 0 - 5000 RPM 0
Speed Enabled Output Turn Off Speed 0 - 8000 RPM 0
Gear Indicator Reverse Enabled Status Disabled, Enabled Disabled
Gear Indicator Neutral Enabled Status Disabled, Enabled Disabled
Gear Indicator 8F Enabled Status Disabled, Enabled Disabled
i03358020 There is an optional gearshift selector. This gearshift

selector uses a J1939 input.
Transmission Control
Note: If you are experiencing trouble with the shifter,
SMCS Code: 3065 refer to Troubleshooting, KENR5099, “Transmission
Does Not Respond to Shift Selector”.
The gearshift selector is a push button switch that
communicates over the data link. The selector has a The transmission for the CX31 has five forward gears,
dual character display with buttons for the following neutral and one reverse gear. The transmission for
functions: the CX35 has six forward gears, neutral and one
reverse gear.
• UP
• DOWN
• FORWARD
• NEUTRAL
• REVERSE
• MODE
20 KENR5099-06
NOTICE
The machine must be stopped and the engine at low
idle before changing direction. After moving the trans-
mission control, do not accelerate until after hearing
or feeling the transmission clutches engage.
When the transmission control is in the NEUTRAL

position (5), the neutral lock prevents the transmission
control from being accidentally moved into a gear
position.
Press the neutral lock switch, and move the

transmission control forward or backward in order to
select the following gears.
“R” – The “R” indicates the reverse gear. Pressing

this button causes the transmission to shift into the
reverse gear.
“N” – The “N” indicates the transmission neutral

position. Pressing this button causes the transmission
to shift to neutral.
“D” – The “D” button indicates the forward gears.

Pressing this button will cause the transmission to
shift into the first gear in the forward direction.
“Mode” – Mode Selector
“Arrow” – Upshift
“Arrow” – Downshift
Stop the vehicle and ensure that the engine is at low

idle. When you move the transmission control from
the NEUTRAL position to the FORWARD position,
the first gear and the torque converter drive will be
engaged.
Illustration 2
g01296757 As you increase engine speed and the ground
speed increases, the transmission will upshift. As the
The transmission control has six buttons. ground speed continues to increase, the transmission
will upshift automatically until the selected gear is
(1) Mode reached.
(2) Upshift Arrow If the ground speed is reduced or the engine speed is
reduced by an increased load, the transmission will
(3) Downshift Arrow automatically downshift in order to select the correct
gear. The transmission downshifts one gear at a time
(4) “D” button in order to select the correct gear.
(5) “N” button A downshift inhibitor prevents the operator from

forcing a downshift. When the vehicle is in motion
(6) “R” button and the gearshift selector is moved to a lower gear,
the transmission will not force a sudden downshift.
Refer to Operation and Maintenance Manual, The transmission will not downshift until the proper
“Transmission Control”. ground speed is achieved.
KENR5099-06 21
Checking the Oil Level The gearshift selector can Manual Selection of the Highest Desired Forward
be used in order to initiate the oil level check. The Gear
check is initiated by pressing the up arrow and the
down arrow on the keypad simultaneously. The status The maximum desired gear of the transmission is
of the oil level is displayed on the digital display. limited for certain operations of the vehicle. When D
is selected, the maximum desired gear is displayed.
By using the up arrows and the down arrows on the
Basic Operation shift pad, the maximum desired gear can be selected.
Pressing the up arrow will raise the maximum
desired gear by one gear to the maximum gear that
is available. Pressing the down arrow will lower the
maximum desired gear by one gear to the minimum
gear that is available.
Once the desired gear is selected, the transmission

will maintain the gear. The transmission will not shift
g01343907
Illustration 3 to a higher gear unless the speed of the vehicle
Display showing the NEUTRAL position. requires a shift. The transmission will shift in order to
protect the engine from an overspeed event. The up
The display on the gearshift selector will display a arrow may be used in order to select the maximum
pair of “Ns” when the key start switch is in the ON gear when the conditions of operation of the vehicle
position. This indicates that the transmission is in no longer require the lower maximum gear.
Neutral.
Reverse Range
Range Selection
Push the “D” in order to shift to a forward gear or the
“R” in order to shift to a reverse gear.
Note: The transmission will not shift into a gear from

Neutral or between a forward “D” and reverse “R”
gear when the engine RPM is over 1000 RPM.
g01343923
Illustration 5
Forward Range Display showing the Reverse gear is selected but the trasmissionis
not shifted from Neutral.
Push the “R” button in order to select the reverse

range. The display on the gearshift selector displays
an “R” on the left side and an “N” on the right side.
g01343917
Illustration 4
Display showing the first gear forward.
Note: 4 shows that the transmission is in first gear

and that a total of 6 gears is available.
g01343924
Illustration 6
The gearshift selector will display the maximum gear Display showing the transmission inReversegear.
that is available on the transmission on the left side
of the display and the actual gear on the right side of When the transmission shifts into a reverse range,
the display when “D” is selected. As the transmission the display will have an “R” in both locations. There is
continues to shift the actual gear is displayed on the only one gear in the reverse range.
right side of the display. An upshift or a downshift may
be forced by pressing one of the arrows on the right Flashing Desired Gear
side of the gearshift selector when the transmission
is in a forward range. Several circumstances may prevent the transmission
from shifting into a desired range.
22 KENR5099-06
Mode Button
g01343927
Illustration 7
The display is showing the desired gear. The transmission is held
in the Neutral position.
Circumstances that prevent shifting into the desired

gear include the following:
• The engine speed is too high.

• Vehicle speed is too high.
• Programmable parameters
• Auto Neutral
• PTO
• Driveline PTO
• Neutral to Gear Inhibit
• Direction Inhibit
Once the switch and the speed requirements have
been met the transmission may shift normally. Some
circumstances may require the operator to select
Neutral and then to select the desired range in order
for the transmission to shift into the range. Illustration 8
g01319024
The “MODE” button is available to control a variety

of functions. The primary purpose of the button is to
select a different shift schedule. The different shift
schedules change the fuel economy. Other modes
may be selected through the programming of the
transmission parameter. When the “MODE” button is
pushed, the LED in the upper right corner turns ON
and informs the operator that the selected feature is
active. Pressing the “MODE” button a second time
disables the feature and the LED turns OFF.
Oil Level Check

The shift selector pad allows the operator to check
the oil level of the transmission for the operator's
station. The following conditions are required for
initiating the oil level check:
• Engine at idle
KENR5099-06 23
• The vehicle is stationary. i02861821
• Transmission oil temperature is more than 80 °C Electronic Control Unit

(176 °F).
SMCS Code: 4812; 7610-DTN
Simultaneously press the up arrow and the down
Table 13
arrow in order to initiate the transmission oil level
check. This action starts a two minute timer. If the Contact Description on CX28 Machine
conditions are not correct for the oil level check to
No. Function
take place, the shift selector pad will display one of
the following display codes in Table 11. J1-1 Keyswitch Input (ON position)
Table 11 J1-2 Engine Speed Sensor +
Display Description J1-3 Engine Speed Sensor −
OL-ES-LO Engine speed is too low. J1-4 Torque Converter Output Speed +
OL-ES-HI Engine speed is too high. J1-5 Torque Converter Output Speed −
OL-TX- N Neutral is not selected. J1-6 Transmission Output Speed A +
OL-OT-LO Oil temperature is too low. J1-7 Transmission Output Speed A −
OL-OT-HI Oil temperature is too high. J1-8 Transmission Output Speed B +
OL-VS-HI Vehicle speed is not zero. J1-9 Transmission Output Speed B −

J1-10 J1587 +
Once the conditions have been met, the range J1-11 Transmission Oil Level Sensor Power
display will show “24” and count down to “0” during 5+
the two minute counter period. At the end of the two
minute countdown, one of the following display codes J1-13 − Battery
in Table 12 will be displayed. The display only shows J1-20 J1587 -
two characters at a time.
J1-21 Sensor Return
Table 12
J1-22 Transmission Oil Temperature Sensor
Display Description
J1-23 − Battery
OL-LO-## Oil level is low by ## quarts.
J1-29 Torque Converter Oil Temperature
OL-HI-## Oil level is high by ## Sensor
quarts.
J1-31 + Battery
OL-OK Oil level is full.
J1-32 ECM Location Enable - DO NOT USE
J1-36 Transmission Oil Level Sensor
The message for the oil level will continue to display
until the operator exits the mode. The mode may be J1-38 + Battery
exited by pressing one of the range buttons or by
J1-48 Fail In Gear Sol
simultaneously pressing the up arrow and the down
arrow. J1-49 Clutch 2 Solenoid
J1-50 Solenoid Return 2
J1-51 Clutch 3 Solenoid
J1-60 Solenoid Return 1
J1-61 Switch to Battery 3
J1-62 Lockup Clutch Solenoid
J1-63 Transmission Oil Filter Bypass Switch
24 KENR5099-06
Table 14 Table 15
Contact Description on CX28 Machine Contact Description on CX31 Machine
No. Function No. Function
J2-1 Keyswitch Input (Key in the START J1-1 Keyswitch Input (ON position)
position)
J1-2 Engine Speed Sensor +
J2-5 Backup Alarm Relay
J1-3 Engine Speed Sensor −
J2-6 PTO Enable Relay
J1-4 Torque Converter Output Speed +
J2-7 Starter Interlock Relay
J1-5 Torque Converter Output Speed −
J2-8 Load Return
J1-6 Transmission Output Speed A +
J2-9 Check Transmission Lamp
J1-7 Transmission Output Speed A −
J2-10 Alternator Start In Gear Lamp
J1-8 Transmission Output Speed B +
J2-11 Gear Driver Output
J1-9 Transmission Output Speed B −
J2-12 Transmission Temperature/Filter
Bypass Lamp J1-10 J1587 +
J2-13 Speed Enable Output J1-11 Oil Level Sensor Power
J2-14 Switch to Battery 1 J1-13 − Battery
J2-19 Output Speed Driver J1-20 J1587 -
J2-26 Quick Gear Limit Switch J1-21 Sensor Return
J2-27 Alternate Start In Gear Switch J1-22 Transmission Oil Temperature Sensor
J2-29 Parking Brake Switch J1-23 − Battery
J2-30 Neutral to Gear Inhibit J1-29 Torque Converter Temperature
J2-31 Direction Inhibit SWG J1-31 + Battery
J2-33 Shift Display Blank Input J1-32 ECM Location Enable - DO NOT USE
J2-34 Economy Mode J1-36 Transmission Oil Level Sensor
J2-35 Shift Selector Input J1-38 + Battery
J2-36 Service Brake Switch J1-48 Fail In Gear Sol/Switch to Battery 2
J2-40 Auto Neutral Input 1 Switch J1-49 Clutch 2 Solenoid
J2-41 Auto Neutral Input 2 Switch J1-50 Solenoid Return 2
J2-46 PTO On/Off 1 Switch J1-51 Clutch 3 Solenoid
J2-47 PTO On/Off 2 Switch J1-52 Clutch 4 Solenoid
J2-54 Driveline PTO Switch J1-58 Clutch 5 Solenoid
J2-55 Hold Gear Switch J1-59 Clutch 1 Solenoid
J2-67 J1939 + J1-60 Solenoid Return 1
J2-68 J1939 - J1-61 Retarder Solenoid/Switch to Battery 3
J2-69 J1939 Shield J1-62 Lockup Clutch Solenoid

J1-63 Transmission Oil Filter Bypass Switch
KENR5099-06 25
Table 16 Table 17
Contact Description on CX31 Machine Contact Description on CX35 Machine
J2-1 Keyswitch Input (Key in the START J1-1 Keyswitch Input (ON position)
position)
J1-2 Engine Speed Sensor +
J1-3 Engine Speed Sensor −
J2-6 PTO Enable Relay
J1-4 Torque Converter Output Speed +
J2-7 Start Interlock Relay
J1-5 Torque Converter Output Speed −
J2-8 Load Return
J1-6 Transmission Output Speed A +
J1-7 Transmission Output Speed A −
J1-8 Transmission Output Speed B +
J1-9 Transmission Output Speed B −
Bypass Lamp J1-10 J1587 ATA +
J2-13 Speed Enable Output J1-11 Oil Level Sensor Power
J2-14 Switch to Battery 1 J1-13 − Battery
J2-19 Speedometer Driver Output J1-20 J1587 ATA -
J2-22 Sensor Common J1-21 Oil Level Sensor Return
J2-23 Retarder Shift Point Enable Switch J1-22 Transmission Oil Temperature Sensor
J2-26 Quick Gear Limit J1-23 − Battery
J2-27 Alternate Start In Gear Switch J1-29 Torque Converter Temperature
J2-29 Parking Brake Switch J1-31 + Battery
J2-30 Neutral to Gear Inhibit Switch J1-32 ECM Location Enable - Do Not Use
J2-31 Direction Inhibit Switch J1-36 Oil Level
J2-33 Shift Display Blank Input J1-38 + Battery
J2-34 Economy Mode J1-48 Clutch 6 Solenoid
J2-35 Shift Selector Input J1-49 Clutch 2 Solenoid
J2-36 Service Brake Switch J1-50 Solenoid Return 2
J2-38 Retarder Medium J1-51 Clutch 3 Solenoid
J2-40 Auto Neutral Switch Input 1 J1-52 Clutch 4 Solenoid
J2-41 Auto Neutral Switch Input 2 J1-55 Retarder Solenoid Return
J2-42 Retarder Lo/High J1-58 Clutch 5 Solenoid
J2-46 PTO Enable Switch 1 J1-59 Clutch 1 Solenoid
J2-54 Driveline PTO Switch J1-60 Solenoid Return
J2-55 Hold Gear Switch J1-61 Fail In Gear Solenoid
J2-64 Driveline PTO Engaged Input J1-62 Lockup Clutch Solenoid
J2-67 J1939 + J1-63 Transmission Oil Filter Bypass Switch
J2-68 J1939 - J1-65 Retarder Solenoid
J2-69 J1939 Shield J1-70 − Battery

26 KENR5099-06
Table 18 Table 19
Contact Description on CX35 Machine Contact Description on 12 Pin Connector
J2-1 Keyswitch Input (Key in the START 1 CAN HI
position)
2 Shift Selector ID 1
3 Ignition
J2-6 PTO Enable
4 Unused
J2-7 Start Relay
5 J1939 Shield
J2-8 Load Return
6 Display Dimmer
7 CAN LOW
8 Shift Selector ID 2
9 Unused
Bypass Lamp 10 Unused
J2-13 Speed Enable Output 11 + Battery (Unswitched)
J2-14 Switch to Battery 1 12 - Battery (Ground)
J2-19 Output Speed Driver

Table 20
J2-22 Sensor Common Contact Description on 24 Pin Connector
J2-23 Retarder Shift Point Enable Switch No. Function
J2-26 Quick Gear Limit 1 + Battery
J2-28 Alternate Start In Gear Switch 2 Switch to Battery 2
J2-29 Parking Brake 3 + Battery
J2-30 Neutral to Gear Inhibit 4 Unused
J2-31 Direction Inhibit SWG 5 Switch to Battery 3
J2-33 Shift Display Blank Input 6 Unused
J2-34 Economy Mode 7 Ignition Switch
J2-35 Shift Selector Input 8 Unused
J2-36 Service Brake 9 Unused
J2-38 Retarder Medium 10 Unused
J2-40 Auto Neutral Input 1 11 Unused
J2-41 Auto Neutral Input 2 12 J1587 +
J2-42 Retarder Lo/High 13 Unused
J2-46 PTO Enable Switch 1 14 Unused
J2-47 PTO Enable Switch 2 15 Unused
J2-54 Driveline PTO Engaged 16 Unused
J2-55 Hold Gear 17 - Battery
J2-67 J1939 + 18 J1587 -
J2-68 J1939 - 19 - Battery
J2-69 J1939 Shield 20 Unused
21 Unused
22 Unused
23 Unused
24 Unused
KENR5099-06 27
Inputs
Numerous inputs to the electronic control unit are
used in order to interrelate with the chassis and to
monitor the condition of the transmission. Two types
of inputs exist. One type of input is the switch input.
The other input device is a sensor. Switches and
harness wiring provide signals to the switch inputs
of the electronic control module. Switch conditions
include open circuit, short to +battery, and short to
ground. Sensors provide monitored condition signals
to the sensor input of the electronic control unit.
Outputs
g01255959
Illustration 9
Transmission ECU
The electronic control module responds to decisions
by sending electrical signals through various outputs.
(1) ConnectorJ1
(2) ConnectorJ2
The outputs are used for all of the following items:
• Create an action.
• Provide information to other devices.
• Supply sensor power.
Input/Output
The SAE J1939 Data Link is used to communicate
with a service tool or other electronic control
modules (if equipped). The data link is bidirectional.
Bidirectional communication allows sharing of
information.
g01296923
Illustration 10
i03486620
OEM 24-pin connector
Decisions are made by the circuits in the electronic

Input Components
control module. Software in the electronic control unit SMCS Code: 1435; 1439; 7332
activates the electronic circuits in the appropriate
way to correctly operate the vehicle. Connectors join
the harness wiring to the inputs and outputs of the Sensors
electronic control unit. There are two connectors with
70 contacts. Complete diagnostic trouble codes are Sensors provide information to inputs of the ECU
available with the ET. about actual transmission conditions. The ECU
receives information from the sensor for speed and
The electronic control unit monitors the condition of temperature. The sensor signal will change in order
the vehicle for Proper system operation. Components to reflect changes in the monitored condition. The
sense the condition of the vehicle. Components then ECU sends this information out on the data link to the
send electrical signals to the inputs of the electronic instrument clusters and other data link devices. The
control unit. The electronic control unit compares the ECU recognizes three types of sensor signals.
information from the inputs to the stored information.
The electronic control unit then decides if outputs will Frequency - The sensor produces an AC signal.
be activated. The activation is performed by sending The AC signal frequency (Hz) varies as the condition
electrical signals through the outputs to an electronic changes.
circuit.
Pulse width modulated - The sensor produces a
digital signal. The duty cycle of the digital signal
varies as the condition changes and the frequency of
the digital signal is constant.
28 KENR5099-06
Voltage - The sensor produces a voltage in reference The transmission oil temperature sensor that is
to the measured condition. A change in the condition located on the transmission sump is a passive
results in a change in voltage at the ECU signal input magnetic sensor that has two wires.
pin.
Oil Level Sensor (Transmission)
Torque Converter Temperature
Sensor
g01824773
Illustration 13
Illustration 11
g01213764 The oil level sensor measures the oil level using the
Hall Effect. As fluid enters the bottom of the sensor
The torque converter temperature sensor that is the internal float moves axially toward the Hall Effect
located on the torque converter is a passive magnetic device. The result is an output signal between 1 Volt
sensor that has two wires. This sensor is used to (empty) and 4 Volts (full) proportional to the fluid
measure the temperatures of the coolant, oil, and level. The sensor connects to the ECU at contact
the inlet air. J1-21, contact J1-11 and contact J1-36.
Transmission Oil Temperature Engine Speed Sensor

Sensor
g01213770
Illustration 14
Engine Speed Sensor
The engine speed sensor for the transmission is a

magnetic sensor.
g01213764
Illustration 12
KENR5099-06 29
The engine speed sensor is an input to the ECU. The The transmission output speed sensors are an input
sensor is designed to inform the ECU about the speed to the ECU. The transmission output speed sensor
of the engine. The ECU uses the information from the informs the ECU about the speed of the transmission
speed sensor in order to calibrate the transmission output shaft. The ECU uses the information from
solenoids. The ECU uses the information from the the transmission output speed sensors in order to
speed sensor in order to enable the lockup clutch. properly shift the transmission. The transmission
Also, the information is used in order to disable the output speed sensor is a magnetic sensor. The
lockup clutch. The lockup clutch is turned off if the output speed sensor is a “bolt and go” sensor that is
engine speed is too low. The lockup clutch is turned a high output speed sensor. There are two output
on if the engine speed is too high. This is done in speed sensors for each transmission. The sensors
order to prevent overspeeds of the engine or stalling read the same speed. The second sensor provides a
of the engine. backup value in the event of a single sensor failure.
The direction is also provided when both sensors
The engine speed sensor is a frequency sensor. The are used. The first sensor is spaced one quarter of
speed sensor is located on the flywheel housing. a tooth off from the second sensor. The space is
The sensor generates an AC signal from the ring necessary in order to provide a direction to the ECU.
gear teeth as the teeth pass the sensor. The ECU When one of the sensors goes bad or a failure arises
measures the frequency of the signal and the ECU a diagnostic code is issued, but a valid engine speed
responds accordingly to the signal. The engine speed is still present. The transmission output speed sensor
and the diagnostic status of the sensor are available (1) connects to the ECU through contacts J1-6 and
to all modules through the J1939 data link. contact J1-7. The transmission output speed sensor
(2) connects to the ECU through contacts J1-8 and
The engine speed sensor has a connector with two contact J1-9.
contacts. The sensor connects to the ECU through
contacts J1-2 and contact J1-3.
Transmission Output Speed Sensor
Transmission Output Speed Sensor (Torque Converter)
(1) and Transmission Output Speed
Sensor (2)
g01213770
Illustration 16
The speed sensor is an input to the ECU. The sensor

g01213770 informs the Transmission ECU about the speed of
Illustration 15
the transmission input shaft. The ECU uses the
Transmission Output Speed Sensor (1)
information from the sensor in order to validate the
Transmission Output Speed Sensor (2) signals for the output speed sensors. When the
output speed sensor fails an amber warning lamp
is activated. The ECU also uses the information to
aid in calibration of the transmission clutches. The
sensor connects to the ECU through contacts J1-4
and contact J1-5.
The ECU records a diagnostic trouble code with the

torque converter output speed sensor with a CID
0673.
30 KENR5099-06
Switches • When a switch is closed, a ground signal or a

+battery signal is provided to the corresponding
Table 21 input of the ECU.
Switch Conditions
Switch Switch State Action Bypass Switch (Transmission
Open Pedal released Filter)
Service Brake
Closed Pedal applied
Open Pedal released
Park Brake
Closed Pedal applied
Neutral to Gear Open Feature enabled

Inhibit Closed Feature disabled
Open Feature enabled
Direction Inhibit
Closed Feature disabled
Auto Neutral Open Feature enabled

(Single Switch) Closed Feature disabled
Auto Neutral Open Feature enabled g01258145

Illustration 17
(Dual SWG) Closed Feature disabled
Open Primary shifter
The bypass switch is a pressure switch that shows
whether the filter is plugged and the filter is being
Shifter Select Closed Secondary bypassed. This switch is Normally Closed. When
shifter electrical power is applied to the switch, the switch
Open Feature disabled closes. When the filter becomes plugged the
PTO Enable pressure of the oil opens the switch and allows the
Closed Feature enabled oil to bypass the filter. The switch is spring loaded.
Open Bypassing When the switch is not installed on a machine the
Transmission spring forces the switch open.
Filter Bypass Closed Not bypassing
Shifter Display Open Display On Key Start Switch

Blank Closed Display Off
The key start switch is an input of the ECU. The
Retarder Shift Open Feature enabled switch tells the ECU that the operator wants to
Enable Closed Feature disabled
start the engine. The ECU then initiates the neutral
start function. See Systems Operation, “System
Open Retarder range Protection Functions” for more information on the
selection neutral start function. See Systems Operation,
disabled “Additional Functions” for more information on the
Retarder On/Off
Closed Retarder range starter interlock function. The signal is open during
selection normal operation. When the key start switch is in the
enabled START position, the switch is closed to the +battery
circuit. Battery power is provided to contact J2-1
Open Feature disabled
when the switch is in the START position.
and 1st gear is
Alternate Start In the lowest range
The ECU records a diagnostic trouble code that
Gear Closed Feature enabled occurs with the key start switch as SPN 158 FMI 2.
and 2nd gear is
the lowest range
Switches provide the following types of information

to the inputs of the Transmission ECU: open signals,
ground signals, and +battery signals. Switches are
open or closed.
• When a switch is open, no signal is provided to the

corresponding input of the ECU. This “no signal”
condition is also called “floating”.
KENR5099-06 31
i02590696 The software will keep a list of available gears when

a diagnostic trouble code occurs. If the control lever
Output Components selects neutral, then the only way to get back to
a selected gear is by shifting to neutral and then
SMCS Code: 3139; 4493; 5479; 7431 back into gear. For example, if the transmission is in
reverse and clutch 3 is an opened circuit, then the
Solenoids transmission shifts to neutral and stays there until the
operator selects neutral and reselects either forward
The solenoid valves are some of the outputs of or reverse. When a diagnostic trouble code occurs,
the Transmission ECU. These solenoids are the if the current gear is available, then the control will
proportional type. The ECU uses a pulse width remain in that gear. But if the diagnostic trouble code
modulated signal (PWM) to vary the current to is present on an active clutch, then the software has
the solenoid. The distance that is travelled by the to determine the appropriate desired gear. When a
solenoid valve is proportional to the electrical current. diagnostic trouble code goes active, the default logic
The position of the valve controls the flow of the oil will pick the next available lower gear as long as the
to the hydraulic cylinder. output speed does not exceed the maximum output
speed allowed for that gear. If a lower gear is not
available or the output speed is too high for that gear,
Transmission Shift Solenoids
then select the next higher gear available.
Transmission Lockup Clutch Solenoid
g01237747
Illustration 18
The solenoid will work for either 12 Volt or 24 volt

g01237747
systems. The medium 12 volt ECPC valve will be Illustration 19
used for all transmission clutches and the lockup
clutch on the OEM On-highway truck transmissions. The Transmission ECU uses the solenoid valve
This solenoid valve is driven by a pulse width to directly modulate the oil pressure to each
modulated signal from the ECU. transmission clutch. The ECU uses a pulse width
modulated signal in order to vary the current to
When a clutch solenoid is shorted to ground or an the solenoid. The solenoid current determines
opened circuit, then all gears that use that clutch the amount of oil pressure that is applied to each
are not available. If a clutch solenoid is shorted clutch. The travel distance of the solenoid plunger is
to +battery, then only gears with that clutch are proportional to the amount of electrical current that
available. If more than one clutch is shorted to is being sent to the solenoid. The position of the
+battery, then the control cannot do anything and solenoid plunger controls the amount of oil pressure
goes to no clutch neutral until fixed. Whenever a and the amount of clutch engagement. An increase
clutch solenoid has failed, the lockup clutch is turned in the electrical current will open the solenoid valve
off. further. This causes and increase in oil pressure.
The transmission lockup clutch solenoid connects to

the ECU at contact J1-60 and contact J1-62.
Output Drivers
Note: If you are experiencing problems with a
driver that has been replaced, see Symptom
Troubleshooting, KENR5099, “Replaced Relay or
Solenoid Does Not Operate”.
32 KENR5099-06
Starter Interlock Driver The messages detailed below are supported.
The driver has the ability to drive up to 2 amps. For

the electrical connections, see Testing and Adjusting,
KENR5099, “System Schematic”.
Backup Alarm Driver

The driver has the ability to drive up to 2 amps. This
driver allows the backup alarm to sound. For the
electrical connections, see Testing and Adjusting,
Output Speed Driver

The driver has the ability to drive up to 300 milliamps.
The output is for driving the speedometer in the
dash. For the electrical connections, see Testing and
Adjusting, KENR5099, “System Schematic”. The
+battery contact of the speedometer connects at the
positive battery terminal.
Speed Enable Driver

The possibilities of the driver include controlling a
steerable axle feature, an automatic lowering of the
chassis, or preventing a door from opening until the
vehicle is stopped. This feature can be programmed
to monitor one of three different speeds. The three
speeds are the engine speed, PTO engine speed,
and the transmission output speed. The feature
monitors the engine speed that is broadcast over
J1939 data link when the relay is programmed to the
engine speed. The ECU monitors the transmissions
PTO shaft speed when the relay is programmed to
the PTO engine speed. The ECU monitors the output
shaft speed of the transmission when the driver is
programmed to the transmission output speed. The
driver connects to the ECU at contact J2-13. For the
electrical connections, see Testing and Adjusting,
Gear Output Driver

For the electrical connections, see Testing and
Adjusting, KENR5099, “System Schematic”.
i02590705
Data Link
SMCS Code: 1408
SAE J1939
A SAE J1939 compliant data link is required for
communication with service tool (Cat ET), engines,
anti-lock brake (ABS), and traction control systems
(TCS), as well as instrument clusters, electronic
control units and other devices that use this
communications protocol.
KENR5099-06 33
Table 22
J1939 (PGN) Parameter Name Receive/Broadcast From To
0 Torque Speed Control Broadcast Trans Engine
1:TSC1
0 Torque Speed Control Receive ABS Trans
1:TSC1
256 Transmission Control 1 Receive Shift Selector Trans
256 Transmission Control 1 Receive ABS Trans
57344 Cab Message 1 : CM1 Broadcast Trans Engine
61440 Electronic Retarder Receive Retarder
Control : ERC1
61440 Electronic Retarder Broadcast Trans
Control : ERC1
61441 Electronic Brake Receive Brake
Controller 1 - EBC1
61442 Electronic Broadcast Trans
Transmission
Controller 1 : ETC1
61443 Electronic Engine Receive Engine
Controller 2 - EEC2
Controller 1 - EEC1
Transmission
Controller 2: ETC2
Transmission
Controller 7: ETC7
65135 Adaptive Cruise Control Receive Body Control
ACC1
65226 Diagnostic Message 1 Broadcast Trans
- DM1
Controller 3 - EEC3
65250 Transmission Broadcast Trans
Configuration : TCFG
65251 Engine Configuration : Receive Engine
EC
65261 Cruise Control/Vehicle Request/Receive Engine
Speed Setup - CCSS
65265 Cruise Control/Vehicle Receive Engine
Speed - CCVS
65265 Cruise Control/Vehicle Receive Body Control
Speed - CCVS
65265 Cruise Control/Vehicle Receive Cab Control
Speed - CCVS
65265 Cruise Control/Vehicle Receive Instrument Cluster
Speed - CCVS
65272 Transmission Fluids : Broadcast Trans
TF
34 KENR5099-06
The SAE J1939 data link provides a method by which

the transmission can limit speed/torque of engine or
do a speed override of the engine.
Using the SAE J1939 data link, the transmission

can send TSC1 messages to the engine to limit
the torque output of the engine during a shift. This
may be needed for protecting the transmission
mechanical parts or it could be used just to improve
the shift quality. There are two different needs for
torque/speed limiting. One is during the shifts,
the second type of torque limiting is needed by
the transmission when the transmission is at stall
condition. The engine speed will be limited to keep
too high of a torque from being transmitted through
the transmission.
SAE J1587
The SAE J1587 data link is supported for instrument
cluster communication. The J1587 data link is not
used in order to broadcast any diagnostic information.
Table 23
PID MID Description
120 222 Hydraulic Retarder Oil Temperature
124 130 Transmission Oil Level
125 130 Transmission Oil Level (Hi/Low)
126 130 Transmission Filter Differential
Pressure
161 130 Input Shaft Speed
162 130 Transmission Range Selected
163 130 Transmission Range Attained
177 130 Transmission Oil Temperature
191 130 Transmission Output Shaft Speed
44 130 Warning Lamp Indicator
KENR5099-06 35
Troubleshooting Section
Troubleshooting Section When you are removing the machine harness from
any ECU, use the single screw in the center of the
harness connector.
Introduction i02535629
i02987926
Service Tools
General Information SMCS Code: 0785
SMCS Code: 4800 The following service tools should be used to aid in
troubleshooting the electrical system.
The diagnostics for a system's ECU can be accessed
through the Caterpillar Electronic Technician (Cat Table 24
ET). Troubleshooting a system requires additional Service Tools
information from the vehicle's Service Manual. The
additional manuals that may be required are the Part Number Part
Machine Monitor System, the Electrical System Caterpillar Electronic Technician (ET)
Schematic, the Parts Manual and the Operation and
Maintenance Manual for the vehicle that is being 6V-7070 Digital Multimeter
9U-7330
serviced.
8T-3224 Needle Tip Group
As a reference, a simplified system schematic is
7X-1710 Multimeter Probe Group
included at the end of this manual. For an accurate
representation of the vehicle that is being diagnosed, 8T-8726 Adapter Cable Assembly
refer to Electrical System Schematic in the Service
9U-7246 Connector Repair Kit
Manual for the vehicle that is being serviced.
DT
When the troubleshooting procedure instructs you 4C-3406 Connector Repair Kit
to “REPAIR THE HARNESS OR REPLACE THE
4C-8195 Control Service Tool (Switch Box)
HARNESS”, use the Electrical System Schematic for
the vehicle that is being serviced to trace the circuit. 157-4829 Cable Adapter
Perform continuity checks at the harness connectors
in order to locate harness failures. At the connectors
of the components, always check the ground circuit.
There must be less than five ohms of resistance
between any system ground and the frame ground.
Excessive ground resistance that is greater than five
ohms can cause incorrect diagnosing of problems.
During troubleshooting, inspect all connections before

any component is replaced. If these connections are
not clean and tight, permanent electrical problems or
intermittent electrical problems can result. Check that
the wires are pushed into the connectors completely.
Make sure that the connections are tight before other
tests are made.
If wire insulation is punctured during troubleshooting,

repair the damage. Seal the damaged wires with
8T-0065 RTV Silicone Sealant. Cover the sealant
with two layers of 1P-0810 Tape.
Failure of an electrical component can cause the

failure of other components. Also, failure of an
electrical component can be caused by the failure
of other components. Always attempt to correct the
cause of an electrical system failure before you
replace a component.
36 KENR5099-06
The Cat ET is used to communicate to the electronic

control module over the data link by connecting
to the machine diagnostic connector. For more
information and the locations of the connectors,
see Troubleshooting, “Electrical Components and
Connector Locations” and the Electrical System
Schematic in your vehicle's Service Manual.
For instructions on servicing Sure Seal connectors,

see Special Instruction, SMHS7531. For instructions
on servicing Deutsch connectors, see Special
Instruction, SEHS9615.
Use the digital multimeter for measuring resistance

or for measuring voltage. For instructions about the
use of the 6V-7070 Digital Multimeter, see Special
Instruction, SEHS7734. The 7X-1710 Multimeter
Probe measures the voltage at the connectors
without disconnecting the connectors. The probe
cables are pushed into the back of the connector
along the wire. The 8T-8726 Adapter Cable has a
Illustration 20
g00774942 breakout with 3 pins. The adapter cable is used for
Connections for the Communication Adapter II and the Caterpillar
measurements in the sensor circuits.
Electronic Technician (ET)
The components that are needed in order to use the
Note: Except for harness tests, using continuity
Communication Adapter II and the Caterpillar Electronic Technician testers such as the 8T-0500 Continuity Tester or
( ET) in order to determine diagnostic trouble codes are listed: voltage testers such as the 5P-7277 Voltage Tester
(6) Cable is not recommended for today's Caterpillar electrical
(7) 171-4400 Communication Adapter II circuits.
(8) Service diagnostic cable.
(9) Current version of Cat ET software and an IBM-COMPATIBLE
personal computer i03003347
Reference: See Special Publication, NEHS0758, Connector Locations

“Communications Adapter II User's Manual Contains
Software”. SMCS Code: 7553-546-WW
Note: Caterpillar Electronic Technician (ET) is a The Electrical System Schematic, Parts Manual and
software program that can be used on an IBM Operation and Maintenance Manual for the vehicle
compatible personal computer. that is being serviced should be used to locate
electrical components and connectors.
In order to use the Cat ET, order the following
materials: Special Publication, JERD2124, “ET The following information is a guide to reading
Single Use Program License”, Special Publication, the tables on the back of the Electrical System
JEHP1026, “Information and Requirements Sheet”, Schematic.
7X-1425 Data Link Cable and the Data Subscription,
and Special Publication, JERD2142, “Data • The “Component Location” table uses white circles
Subscription”. The Special Publication, JEHP1026, to mark the locations in the profile of the vehicle
“Information and Requirements Sheet” lists the and in the area views. Alphabetical letters in the
required hardware and the features of the Cat ET. “Machine Location” column indicate a general area
of the vehicle. Refer to the corresponding footnote
The Cat ET is not required in order to determine at the end of the table for a description of the
the diagnostic trouble codes and the Cat ET is not location.
required in order to clear the diagnostic trouble
codes. However, the process of determining the • The “Harness Connector Location” table uses
diagnostic trouble codes is easier and faster by using white circles to mark the locations in the general
the Cat ET. The Cat ET can also display information view and in the area views. Alphabetical letters in
on the history of a diagnostic trouble code and the the “Machine Location” column indicate a general
parameter status of diagnostic trouble codes. These area of the vehicle. Refer to the corresponding
features allow the Cat ET to be a useful tool for footnote at the end of the table for a description
troubleshooting. of the location.
KENR5099-06 37
g01522216
Illustration 21
(5) J3 Connector (6) J2 Connector (7) J1 Connector
Harness Connectors
g01255959
Illustration 22
Electronic Control Unit (ECU)
38 KENR5099-06
g01255962
Illustration 23
J1 and J2 Harness Connectors that mate to the ECU
OEM Connector
This connector routes power and switch inputs to
the ECU. Crimping and wire specifications for this
connector are similar to the 70 terminal connector.
The figures below show pin, socket locations, and
keys for the 24-pin connector.
g01255115
Illustration 24
J3 Harness Connector
KENR5099-06 39
i03627226
Diagnostic Capabilities
SMCS Code: 4800
The Caterpillar Electronic

Technician (Cat ET)
g00777826
Illustration 25
The Caterpillar Electronic Technician (Cat ET) is a • Print reports.

software program that is used to access data. The
service technician will use the ET in order to perform See Troubleshooting, “Determining Diagnostic
the maintenance on the vehicle. Some of the options Trouble Codes”. Diagnostic information is accessed
that are available with the Cat ET are listed below: with the following drop down menus:
• Diagnosis of problems • Active diagnostic trouble codes

• Viewing diagnostic trouble codes • Logged diagnostic trouble codes
• Viewing active event codes and logged event
codes
• View the status of parameters.

• Clear active diagnostic trouble codes and clear
logged diagnostic trouble codes
• Perform calibration of machine systems.

• Program the ECU (Flash). This is done with the
“WINflash” program. See Testing and Adjusting,
“Electronic Control Unit - Flash Program”.
40 KENR5099-06
Status Groups For The Cat ET
g00912695
Illustration 26
Typical Cat ET screen for parameters
The status groups are lists of machine parameters.

The status of the parameters are shown in real time.
KENR5099-06 41
Symptom Troubleshooting • Check the Auto Neutral Switch status using Cat
ET or a multimeter
i02603681 • Check the Parking Brake Input status using Cat

ET or a mutlimeter
Engine Does Not Crank
SMCS Code: 1000-035; 1450-035 i02603642
The engine does not crank because of causes Transmission Does Not
that are not related to the programming of the Automatically Shift Back Into
transmission. The ignition switch is turned to the
START position and the shifter display goes blank or Gear
changed from “NN” to “--”. The battery is too low to
maintain power to the transmission and/or the shifter. SMCS Code: 3030-035
If the transmissions Starter Interlock Output is used The transmission does not automatically shift back
in order to control the engine starter, check the in to a gear because of a possible failure in the
programming of the following: Auto Neutral feature. This feature may include the
following programming:
• Engine Running Starter Inhibit Enable Status
(Enabled or Disabled) • Auto Neutral Function Enabled Status - Enabled
Check the following: • Auto Neutral Switch Input Configuration - Switch to

Ground, Switch to Battery (1 or 2) or Parking Brake
• While the transmission is in NEUTRAL and the
engine speed is zero, the output should be ON • Auto Neutral Gear Reengagement Brake Required
(+battery voltage) when the Starter Input is ON Configuration (required or not required)
(+battery voltage).
• Auto Neutral Reengagement Configuration
(Disabled, enabled for forward, enabled for forward
i02603324 and reverse or enabled for reverse)
Transmission Does Not • Parking Brake Input Installation Status (Installed
Automatically Shift Into and neutralizer logic is enabled)
Neutral Normal Operation - When the Auto Neutral switch is

closed with the service brake depressed (if required)
SMCS Code: 3030-035 and the Auto Reengagement Configuration is not
programmed to Disabled, the transmission shifts
The transmission does not automatically shift into back in to the previous gear. If the Auto Neutral switch
neutral because of a possible failure in the Auto is programmed to Parking Brake, the parking brake
Neutral enabled feature. This feature requires that input must show activated before the shift is allowed.
the following be programmed:
Check the following:
• Auto Neutral Enabled Status - Enabled
• Verify that the Auto Neutral Switch status is Closed.
• Auto Neutral Switch Input Configuration - Switch to
Ground, Switch to Battery (1 or 2), or Parking Brake • If programmed, the parking brake input must show
disabled.
• Maximum Transmission Output Speed to Enabled
Auto Neutral - above 0 RPM • If the Service Brake is required for automatic
reengagement of a gear, verify that the Service
Normal Operation - With the Auto Neutral Enable Brake switch status is depressed.
programmed to “Enabled”, the transmission output
speed below the programmed “Maximum Output • Verify that the Auto Neutral Reengagement
Speed for Auto Neutral” value and the Auto Neutral Configuration is not programmed to Disabled. If
Switch input open, the transmission should shift the configuration is programmed to Disabled, the
into NEUTRAL. When the switch is programmed to operator is required to select NEUTRAL and the
“Parking Brake”, the parking brake must be activated. forward or reverse range before the transmission
will shift out of NEUTRAL.
Check the following:
42 KENR5099-06
i02603834 The sinking outputs include the Gear Indicator output.

This driver is capable of 0.3 Amps.
Transmission Does Not
Respond to Shift Selector If the replacement of a relay or a solenoid is larger
than the original, meaning that the replacement has a
SMCS Code: 3030-035 higher amperage capability, then the ECU output may
disable in order to keep from destroying the internal
The shifter may not work properly if the transmission parts of the ECU components. A diagnostic trouble
is not connected to the vehicle battery, the ignition code will not be generated in this type of situation.
switch is not connected or the J1939 Data Link is The output will appear not to function.
wiring is disconnected. The shift pad will display “--”
instead of “NN” when the key start switch is turned Perform the following check:
to the ON position.
• Turn the ignition switch OFF. Disconnect the
Check the following: replacement relay or solenoid. Instal a test lamp.
Turn the ignition switch ON and activate the
• Check for battery power to the Transmission ECU. output. If the test lamp indicates that the output is
functional, the replacement relay or solenoid must
• Check for ignition power to the Transmission ECU. be replaced with a relay or solenoid that meets the
origninal specifications. If it is necessary, a smaller
• Check the J1939 Data Link wires and connectors. relay or solenoid can be used in order to operate
the larger relay or solenoid.
• Verify that the correct serial number for the
Transmission ECU has been programmed. There are three outputs that are rated for driving
relays or solenoids. These outputs are rated at 2
See the Testing and Adjusting, “Electrical Connector amps at the chassis battery voltage.
- Inspect” section of this manual for more information.
Table 25
If the shifter only displays the right side digit, the 2 Amp Output Drivers
serial number for the torque converter may not be
Name Pin Location
programmed. Verify that the correct serial number for
the torque converter has been programmed. Backup Alarm Output J2-5
PTO Enable Output J2-6
i02603795
Starter Interlock Output J2-7
Replaced Relay or Solenoid
There are three additional low power drivers that are
Does Not Operate capable of 300 milliamps.
SMCS Code: 4493-035; 5479-035 Table 26
300 mA Output Drivers

Name Pin Location
Output Speed Driver J2-19
Gear Indicator Driver J2-11
Alternate Start in Gear J2-10
Driver
Note: Replacing a driver with one that is rated for a

higher amperage may result in loss of functions. If
a loss of a function results after replacing a driver
or relay, ensure that the replaced driver or relay is
g01303497
properly rated.
Illustration 27
There are two types of outputs. There are driver

outputs and sinking outputs. The driver outputs
include the PTO Latching Output, Starter Interlock
Output and the Backup Alarm. These outputs are
capable of driving 2 Amps of current at battery
voltage.
KENR5099-06 43
Diagnostic Trouble Code (Table 27, contd)

Diagnostic Trouble Codes For The CX
Procedures Series Transmissions
For troubleshooting, see the procedure with the
i02861832 same “SPN” and “FMI”.
Diagnostic Trouble Code List “SPN”/

“CID”
Description
SMCS Code: 7569 FMI 8 Abnormal frequency
Use the instrument cluster or use the Caterpillar FMI 14 Special Instruction
Electronic Technician (Cat ET) in order to determine SPN 513 Engine Torque
the diagnostic trouble codes for the Transmission
ECU. After determining the diagnostic trouble codes, FMI 9 Abnormal update
refer to the corresponding test procedure for more FMI 19 Data error
information. Perform the procedure that corresponds
with the correct diagnostic trouble code. The following SPN 525 Transmission Gear Request
table is a list of possible diagnostic trouble codes for FMI 9 Abnormal update
the ECU.
SPN 639 J1939 Data Link
Table 27 FMI 9 Abnormal update
Diagnostic Trouble Codes For The CX FMI 14 Special Instruction
Series Transmissions
SPN 734 Transmission Clutch Solenoid 1
same “SPN” and “FMI”. FMI 3 Voltage above normal
“SPN”/ Description FMI 5 Current below normal or open circuit
“CID”
FMI 6 Current above normal or closed circuit
SPN 91 Accelerator Pedal
SPN 735 Transmission Clutch Solenoid 2
FMI 9 Abnormal update
FMI 3 Voltage above normal
FMI 19 Data error
FMI 5 Current below normal or open circuit
SPN 126 Transmission Oil Filter Differential Pressure
Sensor FMI 6 Current above normal or closed circuit
FMI 3 Voltage above normal SPN 736 Transmission Clutch Solenoid 3
FMI 16 Data valid but above normal operating range FMI 3 Voltage above normal
(moderate severity) FMI 5 Current below normal or open circuit
SPN 158 Battery Potential (Keyswitch) FMI 6 Current above normal or closed circuit
FMI 2 Data that is erratic, intermittent, or incorrect SPN 737 Transmission Clutch Solenoid 4
SPN 161 Transmission Input Shaft Speed FMI 3 Voltage above normal
FMI 8 Abnormal frequency FMI 5 Current below normal or open circuit
SPN 168 Electrical System Voltage FMI 6 Current above normal or closed circuit
FMI 3 Voltage above normal SPN 738 Transmission Clutch Solenoid 5
FMI 4 Voltage below normal FMI 3 Voltage above normal
SPN 177 Temperature Sensor (Transmission Oil) FMI 5 Current below normal or open circuit
FMI 3 Voltage above normal FMI 6 Current above normal or closed circuit
FMI 4 Voltage below normal SPN 739 Transmission Clutch Solenoid 6
FMI 16 Data valid but above normal operation range FMI 3 Voltage above normal
(moderate severity)
SPN 190 Speed Sensor (Engine)
FMI 8 Abnormal frequency
SPN 740 Transmission Lockup Clutch Solenoid
SPN 191 Transmission Output Speed Sensor
(continued)
(continued)
44 KENR5099-06
(Table 27, contd) i02499653
Diagnostic Trouble Codes For The CX

Series Transmissions
Determining Diagnostic
Trouble Codes
same “SPN” and “FMI”.
SMCS Code: 0785-UE; 7490
“SPN”/ Description
“CID”
Using Caterpillar Electronic
Technician to Determine Diagnostic
Trouble Codes
SPN 744 Retarder Modulation Solenoid
Connect the Caterpillar Electronic Technician (ET)
to the vehicle. Turn the key switch to the RUN
FMI 3 Voltage above normal position. Start the Cat ET. The Cat ET will initiate
communications with the Electronic Control Units
on the vehicle. After communication has been
FMI 6 Current above normal or closed circuit established, the Cat ET will list the Electronic
Control Units. Choose the desired Electronic Control
SPN 973 Engine Retarder Selection
Unit. After the diagnostic trouble codes have been
FMI 9 Abnormal update determined with the Cat ET, see the test procedure
for the corresponding diagnostic trouble code.
FMI 19 Data error
SPN 1716 Non-Engine Retarder Selection Reference: Troubleshooting, “Service Tools”
FMI 8 Abnormal frequency, pulse width, or period
Active Diagnostic Trouble Codes
FMI 13 Out of calibration
SPN 1751 Driver Demanded Torque
FMI 19 Data error
SPN 3027 Transmission Oil Level Sensor
FMI 4 Voltage below normal
SPN 3463 Engagement Status Transfer case output

shaft PTO
FMI 2 Data erratic, intermittent, or incorrect.
SPN 3509 5 Volt Sensor Supply
SPN 3823 Torque Converter Oil Temperature Sensor
FMI 16 Data valid but above normal operation range
(most severe)
SPN 3824 Transmission Latching Gear
SPN 3825 Transmission Output Speed Sensor 2
FMI 8 Abnormal frequency
KENR5099-06 45
g00859671
Illustration 28
Typical Cat ET screen for active diagnostic trouble codes
The following procedures may cause new diagnostic

trouble codes to be logged. Therefore, before any
procedures are performed make a list of all the active
diagnostic trouble codes in order to determine the
system problems. Clear the diagnostic trouble codes
that were caused by the procedure, when each
procedure is complete.
Note: Before performing a procedure, always check

all the circuit breakers. Repair the cause of any circuit
breaker that is tripped.
A screen is provided in Cat ET for active diagnostic

trouble codes. The screen will display the diagnostic
trouble codes that are active. Active diagnostic
information shall include a component identifier
(SPN), a failure mode identifier (FMI) and a text
description of the problem.
Logged Diagnostic Trouble Codes

46 KENR5099-06
g00859762
Illustration 29
Typical Cat ET screen for logged diagnostic trouble codes
A screen is provided in Cat ET for logged diagnostic

trouble codes. The screen will display diagnostic
trouble codes that are logged. The Cat ET will log
diagnostic trouble codes that are intermittent. The
logged diagnostic data shall include a component
identifier (SPN), a failure mode identifier (FMI),
and a text description of the problem. Also, the
logged diagnostic data shall include the number of
occurrences of the problem and two time stamps.
The time stamp displays the first occurrence of the
problem and the time stamp displays the most recent
occurrence of the problem.
Diagnostics are logged in non-volatile memory. On

powerup, the ECU will clear any diagnostic trouble
codes that have not been detected or active within
the last 150 hours of vehicle operation.
KENR5099-06 47
Connecting Cat ET and the Electronic Service Tool Will not

Communication Adapter II Communicate with ECU
Probable Causes
• Configuration for the communications adapter

• J1/P1 connectors for the Engine Control Unit (ECU)
• Communication adapter and/or cables
• Electrical power supply to the service tool
connector
• Caterpillar Electronic Technician (ET) and related

hardware
• Electrical power supply to the ECU

• Override switches
• J1939 data link
Recommended Actions:
1. Electrical Power Supply to the Service Tool
Connector
Verify that the battery voltage is present between

terminal A and terminal B of the service tool
g00647144
Illustration 30 connector. If the commmunication adapter is not
(1) Personal computer (PC) receiving power, the communication adapter's power
(2) 196-0055 Adapter Cable As light will not be on. Proceed to Test Step 2 if the
(3) 171-4401 Communication Adapter As
(4) 207-6845 Adapter Cable As
power light is not illuminated. Try turning the key
off and shutting down Cat ET if the communication
adapter is powered but is still not communicating.
Note: Items (2), (3), and (4) are part of the 171-4400
Communication Adapter II Gp.
2. Communication Adapter and/or Cables
Use the following procedure to connect Cat ET and
the Communication Adapter II. Usure all of the connections are tight and dry.
If you are using a 171-4401 Communication
Adapter Assembly, ensure that the firmware and the
1. Turn the keyswitch to the OFF/RESET position. If
the key switch is not placed in the OFF/RESET software files for the adapter are the most current
position, the engine may start. that are available. If the firmware and the software
do not match, the communication adapter will not
2. Connect cable (2) between the “COMPUTER” communicate with Cat ET. Proceed to Test Step 3.
end of communication adapter (3) and the RS232
3. Cat ET and Related Hardware
serial port of PC (1).
3. Connect cable (4) between the “DATA LINK” end In order to elminate Cat ET and the related hardware
as the problem, connect Cat ET to a different engine.
of communication adapter (3) and the service tool
connector. If the same problem occures on a different engine,
check Cat ET and the related hardware in order to
determine the cause of the problem. If Cat ET and
4. Turn the keyswitch to the ON position. If Cat
ET and the communication adapter do not the hardware are good, proceed to Test Step 4. If you
communicate with the Engine Control Unit (ECU), cannot gain communications on another machine,
proceed to Test Step 8.
proceed to the next Test Step.
4. J1/P1 ECU Connectors
Check the J1/P1 ECU connectors for the following

problems:
48 KENR5099-06
• Proper torque 4. Check for any hardware that is utilizing the same
port as the communications adapter. If any devices
• Cleanliness of the terminals are configured to use the same port, exit or close the
software programs for that device.
• Wires and terminals are properly installed into the
connector.
i02869300
Refer to Testing and Adjusting, “Electrical Connectors

- Inspect” for additional information. Proceed to Test
Transmission, SPN 91 - FMI 9
Step 5. SMCS Code: 1913-038
5. Electrical Power Supply to the ECU Conditions Which Generate This Code:
If the ECU is not receiving battery voltage, The ECU
will not communicate. Check the electrical power to
the ECU. Proceed to Test Step 6 if there is no power
to the ECU.
6. Override Switches
Verify that there are no aftermarket devices that

are preventing battery voltage from reaching the
ECU. Some type of override switch is interrupting the
power to the ECU if the following conditions are true:
• Communication occurs when the engine is running

• No communication occurs when the engine is not Illustration 31
g01350167
running and the key switch is ON

This diagnostic code is associated with the
Try starting the engine and gaining communications. accelerator pedal. The illustration for the J1939
This procedure may solve the communication Data Link may not represent all of the connections
problem. If the problem is not fixed, proceed to Test for the components that are on machines that are
Step 7. covered by this manual. Refer to the electrical system
schematic for your machine in order to verify the
Perform the following procedure: J1939 Data Link connections.
1. Turn the key switch to the OFF position. Note: This diagnostic code is recorded when the
Transmission ECU does not receive expected
2. Discoonect Cat ET. information from the accelerator pedal for a period of
more than five seconds.
3. Turn the key switch to the ON position.
Test Step 1. VERIFY THE HARDWARE
4. Connect Cat ET. AND THE SOFTWARE PART NUMBERS.
7. J1939 Data Link A. Verify that the following information is correct:
Troubleshoot the J1939 data link for possible • The part number of the flash software for the
problems. Refer to troubleshooting the “data link”. Transmission ECU
8. Configuration for the Communications Adapter • The part number of the Transmission ECU
1. Access “Preferences” under the “Utilities” menu Note: Consult the Business Unit that produces the
on Cat ET. product for the correct part numbers of the flash
software.
2. Verify that the correct “Communications Interface
Device” is selected. Expected Result:
3. Verify that the correct “Port” is selected for use by All the part numbers are correct.
the communication adapter. The most commonly
used port is “COM 1”.
KENR5099-06 49
Results: Repair: Repair the machine harness or replace the

machine harness.
• OK – All of the part numbers are correct. Proceed
to Test Step 2. STOP.
• NOT OK – All of the part numbers are not correct. Test Step 3. CHECK FOR SHORTS TO
GROUND
Repair: The ECU has the wrong part number or
the incorrect software is installed. Replace the ECU A. The disconnect switch remains in the OFF
with a module that has the correct part number. position.
Flash the correct software. See the Testing and
Adjusting, “Electronic Control Unit - Flash Program” B. Disconnect the machine harness from all
section of this manual. electronic control modules that use the J1939
Data Link.
STOP.
C. At the machine harness for the Transmission
Test Step 2. INSPECT THE HARNESS ECU, measure the resistance between contacts
CONNECTIONS. J2-67 and J2-68 of the J1939 Data Link and frame
ground.
A. Turn the disconnect switch to the OFF position.
Expected Result:
B. Inspect all harness connections that are related
to the J1939 Data Link. Make sure that the The resistance is greater than 5000 Ohms.
connectors are clean and tight.
Results:
C. Check the connectors for proper mating. Ensure
that all the seals are present and in place. • OK – The resistance is greater than 5000 Ohms.
The harness circuit resistance is correct. Proceed
D. Check the harness for signs of damage or to Test Step 4.
abrasion.
• NOT OK – The resistance is less than 5000 Ohms.
E. Check the wires at the connector. Ensure that the The machine harness has failed.
wires are secured tightly into the connector. Take
care not to pull the wire out of the connector. Repair: There is a short between frame ground
and the J1939 Data Link circuit in the machine
F. Check the exposed wires at the connectors for harness. Repair the machine harness or replace
nicks or signs of abrasion. the machine harness. See the Testing and
Adjusting, “Wiring Harness (Short Circuit) - Test”
G. Check for moisture inside the connector. section of this manual.
H. Check the connectors for dirty contacts or STOP.

corroded contacts.
Test Step 4. CHECK THE MACHINE
I. Check each pin and each socket of the machine HARNESS FOR A SHORT TO THE
harness connectors. Ensure that the contacts +BATTERY CIRCUIT.
are properly installed. The contacts should mate
correctly when the two pieces of the connector A. The disconnect switch remains in the OFF
are placed together. position.
Expected Result: B. All related electronic control modules remain

disconnected from the machine harness.
The machine harness connectors are tight and free
of corrosion. C. At the machine harness connector for the
Transmission ECU, perform the checks that are
Results: listed here:
• OK – The machine harness connectors are tight • Measure the resistance between the connector
and free of corrosion. Proceed to Test Step 3. contact J2-67 and all sources of +battery.
• NOT OK – The machine harness connectors are • Measure the resistance between connector
in need of repair. contact J2-68 and all sources of +battery.
50 KENR5099-06
Expected Result: Repair: Check the circuit again. It is unlikely

that the ECU has failed. Exit this procedure and
The resistance is greater than 5000 Ohms. perform this procedure again. If the cause of the
diagnostic trouble code is not found, replace the
Results: ECU. Prior to replacing an ECU, always contact
your dealership for possible consultation with
• OK – The harness circuit resistance is correct. Caterpillar. This consultation may greatly reduce
Proceed to Test Step 5. repair time. See Testing and Adjusting, “Electronic
Control Unit - Replace”.
The machine harness has failed. STOP.
Repair: There is a short between the +battery • NO – The SPN 91 FMI 9 is not active. The
circuit and the circuits of the J1939 Data Link diagnostic trouble code does not exist at this time.
circuit in the machine harness. Repair the machine The initial diagnostic trouble code was probably
harness or replace the machine harness. See the caused by a poor electrical connection at one of
Testing and Adjusting, “Wiring Harness (Short the harness connectors that was disconnected and
Circuit) - Test” section of this manual. reconnected. Resume normal vehicle operation.
STOP.
STOP.
Test Step 5. CHECK IF THE DIAGNOSTIC i02869604
TROUBLE CODE REMAINS. Transmission, SPN 91 - FMI 19

A. Inspect the harness connectors. Clean the SMCS Code: 1913-038
contacts of the harness connectors and check the
wires for damage to the insulation that is caused Conditions Which Generate This Code:
by excessive heat, battery acid, or chafing.
B. Perform a 45 N (10 lb) pull test on each of the

wires that are associated with the circuit.
C. Reconnect all harness connectors. Make sure

that the harness connectors are fully seated and
that the clips for each connector are completely
fastened.
D. Turn the disconnect switch and the key start

switch to the ON position.
E. Operate the vehicle.
F. Check the status of the SPN 91 FMI 9. g01350167

Illustration 32
Expected Result: This diagnostic code is recorded when the data for
the accelerator pedal is not available on the J1939
The SPN 91 FMI 9 is active. Data Link. The data link is not the cause of this
diagnostic trouble code.
Results:
Note: The illustration for the J1939 Data Link may not
• YES – The SPN 91 FMI 9 is active. The diagnostic represent all of the connections for the components
trouble code has not been corrected. that are on machines that are covered by this
manual. Refer to the electrical system schematic for
your machine in order to verify the J1939 Data Link
connections.
The possible causes of the diagnostic trouble code

are listed:
• The feature is not configured in Cat ET.

• The component has an active diagnostic.
KENR5099-06 51
Test Step 1. VERIFY THE i02603137

CONFIGURATION OF THE FEATURE.
A. Verify that the following information is correct:
SMCS Code: 1439-038
• The parameter is set in Cat ET.
Conditions Which Generate This Code:
Expected Result:
All of the information is correct.
Results:
• OK – All of the information is correct. Proceed to

Test Step 2.
• NOT OK – All of the information is not correct.

Repair: The parameters have not been configured
correctly. See the Systems Operation Section,
“Programmable Parameters” section of this
manual.
STOP.
Test Step 2. CHECK THE ENGINE

CONTROL UNIT FOR ACTIVE
DIAGNOSTIC TROUBLE CODES.
g01253937
Illustration 33
A. Check the Engine control unit for active diagnostic Schematic of the bypass pressure switch for the transmission oil
trouble codes for the speed sensors. filter
Expected Result: This diagnostic trouble code is associated with the

bypass pressure switch for the transmission oil filter.
The Engine control unit has active diagnostic codes The FMI 3 means that the ECU has detected the
for the accelerator pedal. voltage as being above normal when the engine is not
running. The code will change to a FMI 16 when the
Results: engine is running. The bypass switch is a normally
open switch. The switch will become closed when the
• OK – The Engine control unit has active diagnostic switch is installed. The switch will then become open
codes. when the filter is plugged and the oil needs to bypass
the filter in order for the transmission to receive oil.
Repair: Perform the procedures for the accelerator
pedal. Verify that clearing the diagnostic trouble The possible causes of this diagnostic trouble code
codes on the Engine control unit has corrected the are listed:
problem.
• Short to the + battery terminal.
STOP.
• The circuit is open.
• NOT OK – The Engine control unit does not have
active diagnostic codes for the accelerator pedal. • A failed switch
Repair: Contact your dealership for possible • The ECU may have failed. This is unlikely.
consultation with Caterpillar. This consultation may
greatly reduce repair time. Note: The following test procedure may create
other diagnostic trouble codes. Ignore these
STOP. created diagnostic trouble codes and clear these
diagnostic trouble codes when the original diagnostic
trouble code has been corrected. Ensure that the
diagnostic trouble code of SPN 126 FMI 3 is
active before performing this procedure.
52 KENR5099-06
Note: Use a digital multimeter for the measurements Test Step 3. CHECK THE SWITCH FOR
in this procedure. PROPER OPERATION.
Test Step 1. CHECK FOR AN OPEN A. Disconnect the switch and remove the switch from
CIRCUIT. the vehicle.
A. Turn the disconnect switch and the key start B. Replace the switch with a new switch.
C. Observe the status of the diagnostic trouble code.
B. Disconnect the harness from the switch.
Expected Result:
C. Connect a jumper wire to pin 1 and pin 2 of the
harness. The switch is operating correctly and the diagnostic
trouble code is not active.
D. Observe the status of the diagnostic trouble code.
Results:
Expected Result:
• YES – The diagnostic trouble code is not active.
The diagnostic trouble code of SPN 126 FMI 3 is The new switch has corrected the problem. The
still active. original switch was faulty. STOP.
Results: • NO – The diagnostic trouble code is active. The

new switch has not corrected the problem. Proceed
• YES – The diagnostic trouble code is still active. to Test Step 4.
Proceed to 2.
Test Step 4. CHECK IF THE DIAGNOSTIC
• NO – The diagostic trouble code is no longer TROUBLE CODE IS STILL ACTIVE.
active. Proceed to 3.
A. Inspect the harness connectors. Clean the
Test Step 2. CHECK FOR A SHORT contacts of the harness connectors and check the
CIRCUIT TO POSITIVE VOLTAGE. wires for damage to the insulation that is caused
A. The disconnect switch remains in the OFF
position. B. Perform a 45 N (10 lb) pull test on each of the
B. Disconnect the harness from the ECU.
C. At the J1 machine harness connector, measure that the harness connectors are fully seated and
the resistance from contact J1-63 and contact that the clips for each connector are completely
J1-21 to all other J1 and J2 contacts and to all fastened.
possible sources of positive voltage.
Expected Result: switch to the ON position.
The resistance measurement is greater than 5000 E. Operate the vehicle.

ohms for each measurement.
F. Determine if the SPN 126 FMI 3 is active.
Results:
Expected Result:
• OK – The resistance measurement is greater than
5000 ohms for each measurement. The circuit is The SPN 126 FMI 3 is active.
correct. Proceed to Test Step 4.
Results:
• NOT OK – The resistance measurement is
not greater than 5000 ohms for one or more • YES – The SPN 126 FMI 3 is active. The
measurements. A short exists in the circuit. diagnostic trouble code has not been corrected.
Repair: The short is in the circuit with the low

resistance measurement. Repair the harness or
replace the harness. Verify that the problem has
been corrected.
STOP.
KENR5099-06 53
Repair: Check the circuit again. It is unlikely This diagnostic trouble code is associated with the
that the ECU has failed. Exit this procedure and bypass pressure switch for the transmission oil filter.
perform this procedure again. If the cause of the The FMI 16 means that the ECU has determined that
diagnostic trouble code is not found, replace the the oil pressure is above a normal operational range
ECU. Prior to replacing an ECU, always contact when the engine is running. The code will change to
your dealership for possible consultation with a FMI 3 when the engine is not running. The pressure
Caterpillar. This consultation may greatly reduce could cause damage. The bypass switch is a normally
repair time. See Testing and Adjusting, “Electronic open switch. The switch will become closed when the
Control Unit - Replace”. switch is installed. The switch will then become open
when the filter is plugged and the oil needs to bypass
STOP. the filter in order for the transmission to receive oil.
• NO – The SPN 126 FMI 3 is not active. The This diagnostic trouble code is active if the following
diagnostic trouble code does not exist at this time. conditions are met:
The initial diagnostic trouble code was probably
caused by a poor electrical connection at one of • Events for engine overspeed are not active.
the harness connectors that was disconnected and
reconnected. Resume normal vehicle operation. • The diagnostic trouble code of SPN 168 - FMI 4 for
STOP. low battery voltage is not active.
i02504797
• Events for the speeds of the transmission output
shaft are not active.
Transmission, SPN 126 - FMI
• The transmission oil temperature is above 50 °C
16 (122 °F).
SMCS Code: 1439-038 INSPECT THE HARNESS CONNECTIONS.

Conditions Which Generate This Code: A. Turn the disconnect switch to the OFF position.
B. Check the connectors for proper mating.
C. Check the wires at the connector.
D. Check each wire for nicks or signs of abrasion in

the insulation.
E. Check for moisture at the connector.
F. Check the connectors for dirty contacts or

corroded contacts.
G. Check each pin and each socket of the machine

harness connectors.
Expected Result:

of corrosion.
Illustration 34
g01253937 Results:
Schematic of the bypass pressure switch for the transmission oil
filter • OK – The machine harness connectors are tight
and free of corrosion. The oil filter is plugged.
Repair: Replace the oil filter.
STOP.
• NOT OK – The machine harness connectors are

in need of repair.
54 KENR5099-06
Repair: Repair the machine harness or replace the B. Disconnect the J1 connector and the J2
machine harness. connectorfrom the Transmission ECU.
STOP. C. Disconnect the key start switch from the machine

harness connector.
i02862975
D. At the machine harness connector for the
Transmission, SPN 158 - FMI 2 keyswitch, place a jumper wire between contact 3
and contact 1.
SMCS Code: 1408-038
E. Use a multimeter to measure the resistance from
Conditions Which Generate This Code: contact J1-1 to contact J2-1.
The ECU detects the following condition: Expected Result:
The resistance is less than 5 ohms.

• The signal from the keyswitch was rapidly cycled
at least three times within the last second.
Results:
• The diagnostic trouble codes of SPN 168 FMI 4
and SPN 168 FMI 3 are not active. • YES – The resistance is less than 5 ohms. The
circuit is correct. Proceed to Test Step 2.
• The transmission output speed is greater than 0.
• NO – The resistance measurement is greater than
The possible causes of this diagnostic code are 5 ohms. The wiring harness is not correct. A poor
listed: connection exists or an open circuit exists in the
wiring harness.
• The keyswitch is rapidly cycled. Repair: Perform the test for a poor connection.
See Testing and Adjusting, “Eletrical Connector -
• The switch for the starter interlock is the engaged Inspect” for more information. Check the wiring
too long.
harness for an open circuit. See Testing and
Adjusting, “Wiring Harness (Open Circuit) - Test.”
• The contact J2-1 has received battery power for for more information.
longer than ninety seconds.
Note: This diagnostic trouble code can be generated STOP.

by rapidly cycling the keyswitch. Some control units
on the application may require this action in order to Test Step 2. CHECK THE CIRCUIT FOR A
prompt flash codes. If this occurs, clear the logged SHORT TO GROUND.
diagnostic trouble codes in order to prevent future
confusion or an incorrect diagnosis. A. Remove the jumper wire that was installed in the
previous Test Step.
Note: This diagnostic trouble code can be generated
when the starter interlock switch is engaged too long. B. Measure the resistance from contact J1-1 to all of
Turn the switch to the off position in order to clear the the contacts in the machine harness connector
diagnostic trouble code. The keyswitch may need and to frame ground.
to be cycled in order to clear the diagnostic trouble
code. C. Note the resistance measurement.
Note: This diagnostic trouble code can be generated D. Measure the resistance from contact J2-1 to all of
when battery voltage is connected to contact J2-1 the contacts in the machine harness connector
for more than one minute. and to frame ground.
System Response: E. Note the resistance measurement.
The ECU will log the diagnostic trouble code and Expected Result:
the warning lamp will come on while this diagnostic
trouble code is active. The resistance is greater than 5000 ohms for both
measurements.
Test Step 1. CHECK THE HARNESS FOR
AN OPEN CIRCUIT. Results:
A. Turn the key start switch to the OFF position. • YES – The resistance is greater than 5000 ohms
for both measurements. Proceed to Test Step 3.
KENR5099-06 55
• NO – The resistance measurement is less than E. Operate the machine.

5000 ohms. The circuit with the low resistance
measurement has a short. F. Determine if the SPN 158 FMI 2 is active.
Repair: The circuit with the low resistance Expected Result:

measurement has a short. Repair the wiring
harness. See Testing and Adjusting, “Wiring The SPN 158 FMI 2 is active.
Harness (Short Circuit) - Test.” for more
information. Results:
STOP. • YES – The SPN 158 FMI 2 is active. The

diagnostic trouble code has not been corrected.
Test Step 3. CHECK THE CIRCUIT FOR A
SHORT TO +BATTERY. Repair: Check the circuit again. It is unlikely
A. At the machine harness connector for the ECU, perform this procedure again. Prior to replacing an
insert a multimeter probe in contact J2-1. ECU, always contact your dealership for possible
consultation with Caterpillar. This consultation
B. Measure the resistance from J2-1 to all possible may greatly reduce repair time. See Testing and
sources of positive voltage. Adjusting, “Electronic Control Unit - Replace”.
Expected Result: STOP.
The resistance measurement is less than 5 ohms. • NO – The SPN 158 FMI 2 is not active. The
diagnostic trouble code does not exist at this time.
Results: The initial diagnostic trouble code was probably
caused by a poor electrical connection or a
• YES – The resistance measurement is less than short at one of the harness connectors that was
5 ohms. The circuit is shorted to positive voltage. disconnected and reconnected. Resume normal
The circuit is not correct. machine operation. STOP.
Repair: Repair the circuit with the low resistance

i02573651
measurement. Wire L740-BU should not be wired
to the +battery. Repair the machine harness or
replace the machine harness. See Testing and
Adjusting, “Wiring Harness (Short Circuit) - Test.” SMCS Code: 1439-038-T3; 3175-038-IV
for more information.
STOP.
• NO – The resistance measurement is greater than

5 ohms. The circuit is correct. Proceed to Test Step
4.

TROUBLE CODE IS STILL ACTIVE.
wires for damage to the insulation that is caused

wires that are associated with the circuit. g01282398
Illustration 35
Schematic of the torque converter output speed sensor
C. Reconnect all harness connectors in order to
make sure that the connectors are fully seated. This diagnostic trouble code is associated with the
Also, make sure that the clips for each connector torque converter output speed sensor. The FMI 8
are completely fastened. means that the ECU has determined that the signal
frequency or the signal pulse width is not within the
D. Turn the disconnect switch and the key start expected range. This sensor is equipped with a
switch to the ON position. magnet. The sensor creates a voltage when the gear
teeth pass by the magnet.
56 KENR5099-06
This sensor is a frequency sensor. The sensor sends C. Check the connectors for proper mating. Ensure
a frequency to the ECU as the gear teeth pass the that all the seals are present and in place.
magnet. The voltage is proportional to the speed of
the torque converter output shaft. The frequency that D. Check the harness for signs of damage or
is sent to the ECU increases when the speed of the abrasion.
teeth increases.
E. Check the wires at the connector. Ensure that the
The possible causes of this diagnostic trouble code wires are secured tightly into the connector.
are listed below:
F. Perform a 45 N (10 lb) pull test on each of the
• Intermittent connections or poor connections wires that are associated with the circuit. Take
care not to pull the wire out of the connector.
• The sensor is loose.
G. Check the exposed wires at the connectors for
• The sensor has failed. nicks or signs of abrasion.
• The ECU has failed. This is unlikely. H. Check for moisture inside the connector.
Note: The following test procedure may create I. Check the connectors for dirty contacts or
other diagnostic trouble codes. Ignore these corroded contacts.
created diagnostic trouble codes and clear the
diagnostic trouble codes when the original diagnostic J. Check each pin and each socket of the machine
trouble code has been corrected. Ensure that the harness connectors. Ensure that the contacts
diagnostic trouble code of SPN 161 FMI 8 is active are properly installed. The contacts should mate
before performing this procedure. The engine correctly when the two pieces of the connector
must be running in order for the diagnostic are placed together.
trouble code to be active.
Expected Result:
Note: Use a digital multimeter for the measurements
in this procedure. The machine harness connectors are tight and free
of corrosion.
Table 28
Type Low Range High Range Results:
Sensor 1 75 ohms at −40 °C 230 ohms at 120 °C • OK – The machine harness connectors are tight
(−40 °F) (248 °F) and free of corrosion. Proceed to test step 2.
Sensor 2 600 ohms at 1800 ohms at 120 °C
−40 °C (−40 °F) (248 °F) • NOT OK – The machine harness connectors are
in need of repair.
Note: There are two types of speed sensors that can
Repair: Repair the machine harness or replace the
be used in this application. The following test steps
machine harness.
state the values that are for the first type of speed
sensor. Determine the type of speed sensor that is
STOP.
installed on the machine. Make sure that the sensor
has failed before replacing the sensor.
Test Step 2. CHECK THE CIRCUIT FOR
System Response:
AN OPEN.
A. Turn the disconnect switch and the key start
The ECU will determine the speed of the output shaft
switch to the OFF position.
by using a calculated speed. The calculated speed
is determined by using a percentage of the engine
B. Disconnect the harness from the sensor.
speed.
C. At the machine harness connector for the sensor,
Test Step 1. INSPECT THE HARNESS install a jumper wire between contact 1 and
CONNECTIONS. contact 2 of the harness.
D. Disconnect the machine harness connector J1
from the ECU.
to the sensor. Make sure that the connectors are
E. At the J1 machine harness connectors for the
clean and tight.
ECU, measure the resistance from contact J1-4
to J1-5.
KENR5099-06 57
Expected Result: C. Reconnect all harness connectors in order to

make sure that the connectors are fully seated.
There should be less than 5.0 ohms resistance. Also, make sure that the clips for each connector
are completely fastened.
Results:
• YES – The machine harness is correct. Proceed switch to the ON position.
to Test Step 3.
E. Operate the machine.
• NO – There is an open circuit in the machine
harness. The open circuit is in the wire (L910-PK) F. Determine if the SPN 161 FMI 8 is active.
or in the wire (L911-YL) of the machine harness.
Expected Result:
machine harness. The SPN 161 FMI 8 is active.
STOP. Results:
Test Step 3. CHECK THE SENSOR FOR • YES – The SPN 161 FMI 8 is active. The
AN OPEN. diagnostic trouble code has not been corrected.
A. The disconnect switch and the key start switch Repair: Check the circuit again. It is unlikely
remain in the OFF position. that the ECU has failed. Exit this procedure and
perform this procedure again. If the cause of the
B. Remove the jumper wire that was used in the diagnostic trouble code is not found, replace the
previous Test Step. ECU. Prior to replacing an ECU, always contact
C. Remove the sensor from the machine harness. Caterpillar. This consultation may greatly reduce
Insert a multimeter probe in contact 1 and contact repair time. See Testing and Adjusting, “Electronic
2 of the sensor. Control Unit - Replace”.
D. Measure the resistance of the sensor. STOP.
Expected Result: • NO – The SPN 161 FMI 8 is not active. The

The resistance should be between 75 and 230 ohms. The initial diagnostic trouble code was probably
Results: short at one of the harness connectors that was
disconnected and reconnected. Resume normal
• YES – The resistance is between 75 and 230 machine operation. STOP.
ohms. The sensor is correct. Proceed to Test Step
4.
i02492374
• NO – The resistance is not between 75 and 230

ohms. The sensor has failed.
SMCS Code: 1401-038
Repair: Replace the sensor.
STOP.
This diagnostic trouble code is recorded when the
Test Step 4. CHECK IF THE DIAGNOSTIC ECU for the transmission system identifies a system
TROUBLE CODE IS STILL ACTIVE. voltage that is above 32 VDC. This diagnostic trouble
code can only be activated when the engine is
A. Inspect the harness connectors. Clean the running. The code will latch until the conditions for
contacts of the harness connectors and check the a reset have been met. The code will not become
wires for damage to the insulation that is caused active while the engine is OFF. If the code is active,
by excessive heat, battery acid, or chafing. the charging system is charging at an excessive rate.
B. Perform a 45 N (10 lb) pull test on each of the The possible causes of this diagnostic trouble code
wires that are associated with the circuit. are listed:
• Improper operation of voltage regulator

58 KENR5099-06
The most probable cause of this code is a Determine if there are other electrical problems. If
problem with the charging system. there are other electrical problems, there is a problem
with the battery or with the wiring between the battery
CHECK THE CHARGING SYSTEM. and the overcurrent protection devices.
Check the charging system. Continue with this procedure if there are no other
indications of electrical problems.
Results:
A. Do not turn off the engine.
• YES – Perform the test for the charging system.
B. Use Cat Electronic Technician (ET) to view the
Repair: Refer to the charging system test in the value of the “ECM Battery Voltage” parameter.
troubleshooting manual for the engine that is being
serviced. Expected Result:
STOP. The voltage is less than 9.0 VDC.
Results:
i02492375
Transmission, SPN 168 - FMI 4 • The voltage is less than 9.0 VDC – Proceed to
Test Step 2.
SMCS Code: 1401-038
• The voltage is greater than 9.0 VDC. – Cat ET
Conditions Which Generate This Code: indicates a “ECM Battery Voltage” that is greater
than 9.0 VDC. However, there is an active SPN
This diagnostic trouble code is recorded when the 168 FMI 4 code.
ECU detects a battery voltage of less than 9 VDC.
Repair: Replace the ECM. Prior to replacing an
The possible causes of this diagnostic trouble code ECM, always contact your dealership for possible
are listed: consultation with Caterpillar. This consultation
may greatly reduce repair time. See Testing and
Adjusting, “Electronic Control Unit - Replace”.
• Failure in machine wiring harness Verify that the problem is resolved.
• Charging system component failure STOP.
• The ECU has failed. This is unlikely. Test Step 2. Check the Voltage at the
Determine if a battery charger is being used on Battery
the vehicle. Disconnect the charger if one is used.
Recheck for the diagnostic trouble code. Check the Measure the voltage at the battery terminals.
charging system if the diagnostic trouble code is still
active. Expected Result:
Note: The following test procedure may create The voltage is less than 9.0 VDC.
created diagnostic trouble codes and clear these Results:
trouble code has been corrected. Ensure that the • OK – The voltage at the battery terminals is less
diagnostic trouble code of SPN 168 FMI 4 is than 9.0 VDC. There is a problem with the battery
active before performing this procedure. or with the charging system.
Test Step 1. Check the Battery Voltage at Repair: Load test the battery. Replace the battery,
the J1 Connector if necessary. Test the charging system. Refer
to Systems Operation/Testing and Adjusting,
Table 29 “Charging System - Test” in the manual for the
engine that is being serviced.
12 VDC System 24 VDC System
Low Range High Range Low Range High Range STOP.
12 ± 0.5 13 ± 0.5 24 ± 0.5 28 ± 0.5
VDC VDC VDC VDC
• Not OK – The voltage at the battery terminals is
greater than 9.0 VDC. However, the voltage at the
P1 terminals is less than 9.0 VDC.
KENR5099-06 59
Repair: The problem is in the vehicle wiring. The Test Step 1. CHECK THE VOLTAGE AT
voltage drop can be caused by wiring or by a THE SENSOR.
component. Identify the cause of the voltage drop.
Repair the problem, when possible. Replace parts, A. Turn the disconnect switch and the key start
if necessary. Send the vehicle to the OEM dealer switch to the ON position.
for repair, if necessary. Verify that the problem is
resolved. B. Disconnect the sensor from the machine harness.
STOP. C. At the machine harness connector for the sensor,

measure the voltage between contact 1 (wire
428-OR) and contact 2 (wire 202-BK).
i02479122
Transmission, SPN 177 - FMI 3 Expected Result:
SMCS Code: 1439-038-T3; 3194-038-OC The voltage is approximately 5 VDC.
Conditions Which Generate This Code: Results:
• OK – The voltage is approximately 5 VDC.

Proceed to test step 5.
• NOT OK – The voltage is not approximately 5

VDC.
Repair: There is a problem with the machine

harness or the ECU has failed. It is unlikely that
the ECU has failed.
Test Step 2. CHECK FOR AN OPEN IN

THE SUPPLY CIRCUIT.
g01238171
Illustration 36
Schematic of the transmission oil temperature sensor A. The key start switch and the disconnect switch
remain in the ON position.
This diagnostic trouble code is associated with the
transmission oil temperature sensor. The FMI 3 B. The sensor remains disconnected from the
means that the ECU has determined that the voltage machine harness.
of the circuit for the sensor is above normal.
The possible causes of the diagnostic trouble code measure the voltage from contact 1 (wire 428-OR)
are listed: to ground.
• The energize circuit of the sensor is open. Expected Result:
• The sensor has failed. The voltage is approximately 5 VDC.
• The ECU has failed. This is unlikely. Results:
Note: The following test procedure may create • OK – The voltage measurement is approximately
other diagnostic trouble codes. Ignore these 5 VDC. Proceed to test step 3.
created diagnostic trouble codes and clear these
diagnostic trouble codes when the original diagnostic • NOT OK – The voltage does not measure
trouble code has been corrected. Ensure that the approximately 5 DC.
active before performing this procedure. Repair: The supply circuit is not correct. Repair
the circuit or replace the circuit.
in this procedure. Proceed to Test Step 5.
60 KENR5099-06
Test Step 3. CHECK FOR AN OPEN IN Results:

THE RETURN CIRCUIT.
• YES – The diagnostic trouble code remains active.
A. Turn the disconnect switch and the key start The jumper wire does not affect the diagnostic
switch to the OFF position. trouble code. Proceed to Test Step 5.
B. The sensor remains disconnected from the • NO – The diagnostic is no longer active. The
machine harness. sensor has failed.
C. Disconnect the machine harness connector J1 Repair: Replace the sensor. Verify that the new
from the ECU. sensor corrects the problem.
D. At the machine harness connector for the sensor, Proceed to Test Step 5.
install a jumper wire from contact 2 (wire 202-BK)
to ground. Test Step 5. CHECK IF THE DIAGNOSTIC
E. At the machine harness connector for the ECU,
measure the resistance from contact J1-21 (wire A. Inspect the harness connectors. Clean the
202-BK) to ground. contacts of the harness connectors and check the
Expected Result: by excessive heat, battery acid, or chafing.
The resistance measurement is less than 5000 ohms. B. Perform a 45 N (10 lb) pull test on each of the
Results:
• OK – The resistance measurement is less than make sure that the connectors are fully seated.
5000 ohms. The harness is correct. Also, make sure that the clips for each connector
Repair: The sensor has failed. Replace the sensor.
Proceed to Test Step 5. switch to the ON position.
• NOT OK – The resistance that is measured is not E. Operate the machine.

correct.
Repair: There is an open in the machine harness.
The open is in the return circuit with the high Expected Result:
resistance measurement. Repair the harness or
replace the harness. The SPN 177 FMI 3 is active.
Proceed to Test Step 5. Results:
Test Step 4. CHECK THE SENSOR. • YES – The SPN 177 FMI 3 is active. The
switch to the ON position. Do not start the engine. Repair: Check the circuit again. It is unlikely
that the ECU has failed. Replace the sensor. If
B. Disconnect the sensor with the active diagnostic replacing the sensor does not correct the problem,
trouble code from the machine harness. replace the ECU. Prior to replacing an ECU, always
contact your dealership for possible consultation
C. At the machine harness connector for the sensor, with Caterpillar. This consultation may greatly
place a jumper wire from contact 2 (wire 202-BK) reduce repair time. See Testing and Adjusting,
to contact 1 (wire 428-OR). “Electronic Control Unit - Replace”.
D. Observe the status of the SPN 177 FMI 3. STOP.
Expected Result:
The diagnostic trouble code changes from FMI 3 to

FMI 4 as the jumper wire is installed.
KENR5099-06 61
• NO – The SPN 177 FMI 3 is not active. The Results:

The initial diagnostic trouble code was probably • OK – The diagnostic trouble code is active. The
caused by a poor electrical connection or a sensor is not causing the diagnostic trouble code.
short at one of the harness connectors that was The machine harness or the ECU may have failed.
disconnected and reconnected. Resume normal Proceed to test step 2.
machine operation. STOP.
• NOT OK – This diagnostic trouble code is NO
longer active. The machine harness is correct and
i02479123
the ECU is operating properly. The sensor has
Transmission, SPN 177 - FMI 4 failed.
SMCS Code: 1439-038-T3; 3194-038-OC Repair: Replace the sensor.
Conditions Which Generate This Code: STOP.
Test Step 2. CHECK THE SIGNAL

CIRCUIT FOR A SHORT TO GROUND.
A. The sensor remains disconnected from the
machine harness.
B. Turn the key start switch and the disconnect

C. Disconnect the machine harness from the ECU.
D. At the machine harness connector for the ECU,

measure the resistance between the signal
contact and frame ground.
g01238171
Illustration 37
Schematic of the transmission oil temperature sensor Expected Result:
This diagnostic trouble code is recorded when the The resistance is greater than 5.0 ohms.
ECU reads the voltage of the temperature sensor as
being below normal. The voltage of the signal wire is Results:
below normal and/or shorted to ground.
• OK – The resistance is greater than 5.0 ohms.
The possible causes of this diagnostic trouble code The harness circuit resistance is correct. Proceed
are listed here: to test step 3.
• The signal circuit in the machine harness is shorted • NOT OK – Resistance is less than 5.0 ohms. The
to ground. machine harness has failed.
• The sensor has failed. Repair: There is a short between frame ground
and the signal circuit in the machine harness.
• The ECU has failed. This is unlikely. Repair the machine harness or replace the
machine harness.
Test Step 1. CHECK THE SENSOR.
STOP.
switch to the ON position. Test Step 3. CHECK IF THE DIAGNOSTIC
TROUBLE CODE REMAINS.
B. Observe the status of the diagnostic trouble code.
Then disconnect the machine harness from the A. Inspect the harness connectors. Clean the
sensor. contacts of the harness connectors and check the
If the sensor is not the cause of the diagnostic trouble B. Perform a 45 N (10 lb) pull test on each of the
code, the diagnostic trouble code remains active. If wires that are associated with the circuit.
the sensor has failed, the diagnostic trouble code is
NO longer active.
62 KENR5099-06
C. Reconnect all harness connectors. Make sure i02603153

that the clips for each connector are completely Transmission, SPN 177 - FMI
fastened. 16
D. Turn the disconnect switch and the key start SMCS Code: 1439-038-T3; 3194-038-OC
Expected Result:
The diagnostic trouble code is no longer active.
Results:
• YES – The SPN 177 FMI 4 is not active. The

short at one of the harness connectors that was
g01238171
disconnected and reconnected. Resume normal Illustration 38
machine operation. STOP. Schematic of the transmission oil temperature sensor
• NO – The SPN 177 FMI 4 is active. The diagnostic This diagnostic trouble code is associated with the
trouble code has not been corrected. transmission oil temperature sensor. The FMI 16
means that the ECU has determined that the oil
Repair: Check the circuit again. If the Caterpillar temperature is above a normal operational range.
Electronic Technician (ET) is available, use the Cat The temperature could cause severe damage. The
ET service tool in order to perform a “Wiggle Test” ECU reads the resistance from the sensor. A high oil
on the machine wiring harness. The “Wiggle Test” temperature will send a low voltage to the ECU. The
can detect shorts and opens in the machine wiring high temperature sends a voltage that is lower than
harness that are momentary or intermittent. the expected result for the ECU.
It is unlikely that the ECU has failed. Exit this The cause of this diagnostic trouble code is listed:
procedure and perform this procedure again. If
the cause of the diagnostic trouble code is not • The oil temperature has reached 121° ± 8°C
found, replace the ECU. Prior to replacing an (250° ± 14°F).
ECM, always contact your dealership for possible
consultation with Caterpillar. This consultation The conditions that enable this diagnostic trouble
may greatly reduce repair time. See Testing and code are listed:
• The oil level is below the correct level.
STOP.
• An obstruction is keeping the oil cooler from
performing properly.
• The voltage from the sensor is resisted.

Note: The temperature sensor consistently displays a
severely high temperature. There is no problem with
the wires or harness connections. The temperature
sensor may have failed. Perform the following test
steps in order to ensure that the problem is corrected.
Test Step 1. INSPECT THE HARNESS

CONNECTIONS.
B. Check the connectors for proper mating.

KENR5099-06 63
C. Check the wires at the connector. C. Reconnect all harness connectors. Make sure
D. Check each wire for nicks or signs of abrasion in that the clips for each connector are completely
the insulation. fastened.
E. Check for moisture at the connector. D. Turn the disconnect switch and the key start
F. Check the connectors for dirty contacts or
corroded contacts. E. Operate the vehicle.
G. Check each pin and each socket of the machine F. Check the status of the SPN 177 FMI 16.
harness connectors.
Expected Result:
Expected Result:
The SPN 177 FMI 16 is active.
of corrosion. Results:
Results: • YES – The SPN 177 FMI 16 is active. The

• OK – The machine harness connectors are tight
and free of corrosion. Proceed to test step 2. Repair: Check the circuit again. It is unlikely
• NOT OK – The machine harness connectors are perform this procedure again. If the cause of the
in need of repair. diagnostic trouble code is not found, replace the
ECU. Prior to replacing an ECU, always contact
Repair: Repair the machine harness or replace the your dealership for possible consultation with
machine harness. Caterpillar. This consultation may greatly reduce
repair time. See Testing and Adjusting, “Electronic
STOP. Control Unit - Replace”.
Test Step 2. VERIFY THE TEMPERATURE STOP.

OF THE OIL.
• NO – The SPN 177 FMI 16 is not active. The
Check the temperature of the oil. Turn the engine diagnostic trouble code does not exist at this time.
OFF. Wait for ten minutes. The oil pan for the The initial diagnostic trouble code was probably
transmission should be the same temperature as the caused by an elevated oil temperature that is no
oil. Use a heat gun in order to take a measurement of longer present. STOP.
the temperature of the oil pan for the transmission.
i02573702
Results:
• OK – The temperature of the oil is correct. Proceed
to Test Step 3. SMCS Code: 1439-038-ENG; 1907-038
• NOT OK – The temperature of the oil is not correct. Conditions Which Generate This Code:
Repair: Stop the engine until the oil temperature
returns to an acceptable range.
STOP.


wires that are associated with the circuit. g01238128
Illustration 39
Schematic of the engine speed sensor
64 KENR5099-06
This diagnostic trouble code is associated with the B. Inspect all harness connections that are related
engine speed sensor. The FMI 8 means that the ECU to the sensor. Make sure that the connectors are
has determined that the signal frequency is not within clean and tight.
the expected range.
This sensor is a frequency sensor. The sensor sends that all the seals are present and in place.
a frequency to the ECU as the gear teeth pass the
magnet. The voltage is proportional to the speed of D. Check the harness for signs of damage or
the transmission output shaft. The frequency that is abrasion.
sent to the ECU increases when the speed of the
teeth increases. E. Check the wires at the connector. Ensure that the
wires are secured tightly into the connector.
The possible causes of this diagnostic trouble code
are listed below: F. Perform a 45 N (10 lb) pull test on each of the
wires that are associated with the circuit. Take
• Intermittent connections or poor connections care not to pull the wire out of the connector.
• The sensor is loose. G. Check the exposed wires at the connectors for
nicks or signs of abrasion.
• The sensor has failed.
H. Check for moisture inside the connector.
• The ECU has failed. This is unlikely.
I. Check the connectors for dirty contacts or
Note: The following test procedure may create corroded contacts.
created diagnostic trouble codes and clear the J. Check each pin and each socket of the machine
diagnostic trouble codes when the original diagnostic harness connectors. Ensure that the contacts
trouble code has been corrected. Ensure that the are properly installed. The contacts should mate
diagnostic trouble code of SPN 190 FMI 8 is active correctly when the two pieces of the connector
before performing this procedure. The engine are placed together.
must be running in order for the diagnostic
trouble code to be active. Expected Result:
Note: Use a digital multimeter for the measurements The machine harness connectors are tight and free
in this procedure. of corrosion.
Table 30 Results:
Type Low Range High Range
Sensor 1 75 ohms at −40 °C 230 ohms at 120 °C and free of corrosion. Proceed to test step 2.
(−40 °F) (248 °F)
Sensor 2 600 ohms at 1800 ohms at 120 °C • NOT OK – The machine harness connectors are
−40 °C (−40 °F) (248 °F) in need of repair.

Note: There are two types of speed sensors that
machine harness.
can be used in this application. The following test
steps state the values that are for the second speed
STOP.
sensor. Determine the speed sensor on the machine.
Make sure that the sensor has failed before replacing
the sensor.
Test Step 2. CHECK THE CIRCUIT FOR
AN OPEN.
System Response:
The ECU will use the engine speed input that is
communicated over the data link. The engine speed
B. Disconnect the machine harness from the sensor.
will not be determined if the input is not available.
Test Step 1. INSPECT THE HARNESS install a jumper wire between contact 1 and
CONNECTIONS. contact 2 of the harness.
D. Disconnect the machine harness connector J1
from the ECU.
KENR5099-06 65
E. At the J1 machine harness connectors for the B. Perform a 45 N (10 lb) pull test on each of the
ECU, measure the resistance from contact J1-2 wires that are associated with the circuit.
for the sensor to J1-3.
Expected Result: make sure that the connectors are fully seated.
Also, make sure that the clips for each connector
There should be less than 5.0 ohms resistance. are completely fastened.
Results: D. Turn the disconnect switch and the key start

• YES – The machine harness is correct. Proceed
to Test Step 3. E. Operate the machine.
• NO – There is an open circuit in the machine F. Determine if the SPN 190 FMI 8 is active.
harness. The open circuit is in the wire (E964-WH)
or in the wire (E963-BK) of the machine harness. Expected Result:
Repair: Repair the machine harness or replace the The SPN 190 FMI 8 is active.
machine harness.
Results:
STOP.
• YES – The SPN 190 FMI 8 is active. The
Test Step 3. CHECK THE SENSOR FOR diagnostic trouble code has not been corrected.
AN OPEN
Repair: Check the circuit again. It is unlikely
A. The disconnect switch and the key start switch that the ECU has failed. Exit this procedure and
remain in the OFF position. perform this procedure again. If the cause of the
B. Remove the jumper wire that was used in the ECU. Prior to replacing an ECU, always contact
previous Test Step. your dealership for possible consultation with
Caterpillar. This consultation may greatly reduce
C. Remove the sensor from the machine harness. repair time. See Testing and Adjusting, “Electronic
Insert a multimeter probe in contact 1 and contact Control Unit - Replace”.
2 of the sensor.
STOP.
D. Measure the resistance of the sensor.
Expected Result: diagnostic trouble code does not exist at this time.
The resistance should be between 600 and 1800 caused by a poor electrical connection or a
ohms. short at one of the harness connectors that was
Results: machine operation. STOP.
• YES – The resistance is between 600 and 1800

4.

STOP.

66 KENR5099-06
i02573703 System Response:

Transmission, SPN 191 - FMI 8 The ECU will determine the speed of the output shaft
by using the speed of the second output shaft speed
SMCS Code: 1439-038-T3; 3175-038-OJ sensor.
Conditions Which Generate This Code: Test Step 1. INSPECT THE HARNESS
CONNECTIONS.

clean and tight.

that all the seals are present and in place.
D. Check the harness for signs of damage or

abrasion.
g01262188 E. Check the wires at the connector. Ensure that the

Illustration 40
Schematic of the transmission output speed sensor
This diagnostic trouble code is associated with wires that are associated with the circuit. Take
the transmission output speed sensor. The FMI 8 care not to pull the wire out of the connector.
means that the ECU has determined that the signal
frequency is not within the expected range. G. Check the exposed wires at the connectors for
This sensor is a frequency sensor. The sensor sends
a frequency to the ECU as the gear teeth pass the H. Check for moisture inside the connector.
magnet. The voltage is proportional to the speed of
the transmission output shaft. The frequency that is I. Check the connectors for dirty contacts or
sent to the ECU increases when the speed of the corroded contacts.
teeth increases.
J. Check each pin and each socket of the machine
The possible causes of this diagnostic trouble code harness connectors. Ensure that the contacts
are listed below: are properly installed. The contacts should mate
correctly when the two pieces of the connector
• Intermittent connections or poor connections are placed together.
• The sensor is loose. Expected Result:
• The sensor has failed. The machine harness connectors are tight and free
of corrosion.
Results:
Note: The following test procedure may create
and free of corrosion. Proceed to test step 2.
diagnostic trouble code of SPN 191 FMI 8 is active
in need of repair.
before performing this procedure. The engine
must be running in order for the diagnostic Repair: Repair the machine harness or replace the
trouble code to be active. machine harness.
Note: Use a digital multimeter for the measurements STOP.
in this procedure.
KENR5099-06 67
Test Step 2. CHECK THE CIRCUIT FOR • NO – The resistance is not between 600 and 1800
AN OPEN. ohms. The sensor has failed.
A. Turn the disconnect switch and the key start Repair: Replace the sensor.
STOP.
C. At the machine harness connector for the sensor, TROUBLE CODE IS STILL ACTIVE.
install a jumper wire between contact 1 and
contact 2 of the harness. A. Inspect the harness connectors. Clean the
D. Disconnect the machine harness connector J1 wires for damage to the insulation that is caused
from the ECU. by excessive heat, battery acid, or chafing.
E. At the J1 machine harness connectors for the B. Perform a 45 N (10 lb) pull test on each of the
ECU, measure the resistance from contact J1-6 wires that are associated with the circuit.
for the sensor to J1-7.
Expected Result: make sure that the connectors are fully seated.
There should be less than 5.0 ohms resistance. are completely fastened.

to Test Step 3. E. Operate the machine.
• NO – There is an open circuit in the machine F. Determine if the SPN 191 FMI 8 is active.
harness. The open circuit is in the wire (E900-WH)
or in the wire (E901-GN) of the machine harness. Expected Result:
machine harness.
Results:
STOP.
Test Step 3. CHECK THE SENSOR FOR diagnostic trouble code has not been corrected.
AN OPEN.
A. The disconnect switch and the key start switch that the ECU has failed. Exit this procedure and
remain in the OFF position. perform this procedure again. If the cause of the
B. Remove the jumper wire that was used in the ECU. Prior to replacing an ECU, always contact
previous Test Step. your dealership for possible consultation with
C. Remove the sensor from the machine harness. repair time. See Testing and Adjusting, “Electronic
Insert a multimeter probe in contact 1 and contact Control Unit - Replace”.
2 of the sensor.
STOP.
The resistance should be between 600 and 1800 caused by a poor electrical connection or a
ohms. short at one of the harness connectors that was
Results: machine operation. STOP.

4.
68 KENR5099-06
i02558389 Test Step 1. INSPECT THE HARNESS

CONNECTIONS FOR THE SENSORS.
14 A. Turn the disconnect switch to the OFF position.
SMCS Code: 1439-038-T3; 3175-038-OJ B. Inspect all harness connections that are related to
the sensors. Make sure that the connectors are
Conditions Which Generate This Code: clean and tight.


abrasion.
E. Check the wires at the connectors. Ensure that

the wires are secured tightly into the connector.

care not to pull the wire out of the connectors.

g01280661
Illustration 41 nicks or signs of abrasion.
Schematic of the transmission output speed sensors
H. Check for moisture inside the connectors.
two transmission output speed sensors. The FMI I. Check the connectors for dirty contacts or
14 is recorded when the ECU determines that the corroded contacts.
sensors do not agree with each other and with the
output speed sensor for the transmission. J. Check each pin and each socket of the machine
harness connectors. Ensure that the contacts
The following is a list of possible causes of this are properly installed. The contacts should mate
diagnostic trouble code: correctly when the two pieces of the connector
are placed together.
• Intermittent connections or poor connections
Expected Result:
• A sensor is loose.
• A sensor has failed. of corrosion.
• The ECU has failed. This is unlikely. Results:
Note: The following test procedure may create • OK – The machine harness connectors are tight
other diagnostic trouble codes. Ignore these and free of corrosion. Proceed to test step 2.
diagnostic trouble codes when the original diagnostic • NOT OK – The machine harness connectors are
trouble code has been corrected. Ensure that in need of repair.
the diagnostic trouble code of SPN 191 FMI
14 is active before performing this procedure. Repair: Repair the machine harness or replace the
The engine must be running in order for the machine harness.
diagnostic trouble code to be active.
STOP.
in this procedure. Test Step 2. CHECK THE SENSOR
CIRCUIT FOR AN OPEN
System Response:
Shifting of the transmission is inhibited. switch to the OFF position.
B. At the machine harness connector for the sensors,

install a jumper wire. Install a jumper wire between
contact 1 and contact 2 of the harness.
KENR5099-06 69
C. Disconnect the machine harness connector J1 Test Step 4. CHECK THE SENSORS FOR
from the ECU. AN OPEN
D. At the J1 machine harness connectors for the A. The disconnect switch and the key start switch
ECU, measure the resistance from contact J1-6 remain in the OFF position.
for the sensor to J1-7 for the first speed sensor.
B. Remove the jumper wire that was used in the
Expected Result: previous Test Step.
There should be less than 5.0 ohms resistance. C. Remove the sensor from the machine harness.
Insert a multimeter probe in contact 1 and contact
Results: 2 of the sensor.
• YES – The machine harness is correct. Proceed D. Measure the resistance of the sensor.
to Test Step 4.
Expected Result:
harness. The open circuit is in the wire (E900-WH) The resistance should be between 600 and 1800
or in the wire (E901-GN) of the machine harness. ohms.
Repair: Repair the machine harness or replace the Results:

machine harness.
STOP. ohms. The sensor is correct. Proceed to Test Step
5.
Test Step 3. CHECK THE SENSOR
CIRCUIT FOR AN OPEN • NO – The resistance is not between 600 and 1800
switch to the OFF position. Repair: Replace the sensor.
B. At the machine harness connector for the sensors, STOP.

install a jumper wire. Install a jumper wire between
contact 1 and contact 2 of the sensor. Test Step 5. CHECK IF THE DIAGNOSTIC
C. Disconnect the machine harness connector J1
from the ECU. A. Inspect the harness connectors. Clean the
D. At the J1 machine harness connectors for the wires for damage to the insulation that is caused
ECU, measure the resistance from contact J1-8 by excessive heat, battery acid, or chafing.
for the sensor to J1-9 for the second speed sensor.
Expected Result: wires that are associated with the circuit.
There should be less than 5.0 ohms resistance. C. Reconnect all harness connectors in order to
Results: Also, make sure that the clips for each connector
to Test Step 4. D. Turn the disconnect switch and the key start
harness. The open circuit is in the wire (E906-OR) E. Operate the machine.
or in the wire (E907-GY) of the machine harness.
machine harness. Expected Result:
STOP. The SPN 191 FMI 14 is active.

70 KENR5099-06
Results: Test Step 1. VERIFY THE HARDWARE

AND THE SOFTWARE PART NUMBERS.
diagnostic trouble code has not been corrected. A. Verify that the following information is correct:
Repair: Check the circuit again. It is unlikely • The part number of the flash software for the
that the ECU has failed. Exit this procedure and Transmission ECU
diagnostic trouble code is not found, replace the • The part number of the Transmission ECU
your dealership for possible consultation with Note: Consult the Business Unit that produces the
Caterpillar. This consultation may greatly reduce product for the correct part numbers of the flash
repair time. See Testing and Adjusting, “Electronic software.
Expected Result:
STOP.
All the part numbers are correct.
diagnostic trouble code does not exist at this time. Results:
caused by a poor electrical connection or a • OK – All of the part numbers are correct. Proceed
short at one of the harness connectors that was to Test Step 2.
machine operation. STOP. • NOT OK – All of the part numbers are not correct.
Repair: The ECU has the wrong part number or
i02869534
the incorrect software is installed. Replace the ECU
Transmission, SPN 513 - FMI 9 with a module that has the correct part number.
Flash the correct software. See the Testing and
SMCS Code: 7610-038-DTN Adjusting, “Electronic Control Unit - Flash Program”
section of this manual.
STOP.

CONNECTIONS.

to the J1939 Data Link. Make sure that the
connectors are clean and tight.


g01350167 abrasion.
Illustration 42
This diagnostic code is associated with the data E. Check the wires at the connector. Ensure that the
for the engine torque. The illustration for the J1939 wires are secured tightly into the connector. Take
Data Link may not represent all of the connections care not to pull the wire out of the connector.
for the components that are on machines that are
covered by this manual. Refer to the electrical system F. Check the exposed wires at the connectors for
schematic for your machine in order to verify the nicks or signs of abrasion.
J1939 Data Link connections.
G. Check for moisture inside the connector.
Note: This diagnostic code is recorded when the
Transmission ECU does not receive expected H. Check the connectors for dirty contacts or
information about the data for the engine torque for a corroded contacts.
period of more than five seconds.
KENR5099-06 71
I. Check each pin and each socket of the machine Test Step 4. CHECK THE MACHINE
harness connectors. Ensure that the contacts HARNESS FOR A SHORT TO THE
are properly installed. The contacts should mate +BATTERY CIRCUIT.
are placed together. A. The disconnect switch remains in the OFF
position.
Expected Result:
B. All related electronic control modules remain
The machine harness connectors are tight and free disconnected from the machine harness.
of corrosion.
C. At the machine harness connector for the
Results: Transmission ECU, perform the checks that are
listed here:
and free of corrosion. Proceed to Test Step 3. • Measure the resistance between the connector
contact J2-67 and all sources of +battery.
in need of repair. • Measure the resistance between connector
machine harness. Expected Result:
STOP. The resistance is greater than 5000 Ohms.
Test Step 3. CHECK FOR SHORTS TO Results:

GROUND
• OK – The harness circuit resistance is correct.
A. The disconnect switch remains in the OFF Proceed to Test Step 5.
position.
B. Disconnect the machine harness from all The machine harness has failed.
electronic control modules that use the J1939
Data Link. Repair: There is a short between the +battery
circuit and the circuits of the J1939 Data Link
C. At the machine harness for the Transmission circuit in the machine harness. Repair the machine
ECU, measure the resistance between contacts harness or replace the machine harness. See the
J2-67 and J2-68 of the J1939 Data Link and frame Testing and Adjusting, “Wiring Harness (Short
ground. Circuit) - Test” section of this manual.
The resistance is greater than 5000 Ohms. Test Step 5. CHECK IF THE DIAGNOSTIC
Results:
• OK – The resistance is greater than 5000 Ohms. contacts of the harness connectors and check the
The harness circuit resistance is correct. Proceed wires for damage to the insulation that is caused
to Test Step 4. by excessive heat, battery acid, or chafing.
• NOT OK – The resistance is less than 5000 Ohms. B. Perform a 45 N (10 lb) pull test on each of the
The machine harness has failed. wires that are associated with the circuit.
Repair: There is a short between frame ground C. Reconnect all harness connectors. Make sure
and the J1939 Data Link circuit in the machine that the harness connectors are fully seated and
harness. Repair the machine harness or replace that the clips for each connector are completely
the machine harness. See the Testing and fastened.
Adjusting, “Wiring Harness (Short Circuit) - Test”
section of this manual. D. Turn the disconnect switch and the key start
STOP.
F. Check the status of the SPN 513 FMI 9.

72 KENR5099-06
Expected Result: Note: The illustration for the J1939 Data Link may not
represent all of the connections for the components
The SPN 513 FMI 9 is active. that are on machines that are covered by this
manual. Refer to the electrical system schematic for
Results: your machine in order to verify the J1939 Data Link
connections.
diagnostic trouble code has not been corrected. The possible causes of the diagnostic trouble code
are listed:
that the ECU has failed. Exit this procedure and • The feature is not configured in Cat ET.
diagnostic trouble code is not found, replace the • The component has an active diagnostic.
your dealership for possible consultation with Test Step 1. VERIFY THE
Caterpillar. This consultation may greatly reduce CONFIGURATION OF THE FEATURE.
Control Unit - Replace”. A. Verify that the following information is correct:
STOP. • The parameter is set in Cat ET.

• NO – The SPN 513 FMI 9 is not active. The Expected Result:
The initial diagnostic trouble code was probably All of the information is correct.
caused by a poor electrical connection at one of
the harness connectors that was disconnected and Results:
reconnected. Resume normal vehicle operation.
STOP. • OK – All of the information is correct. Proceed to
Test Step 2.
i02869335
Transmission, SPN 513 - FMI Repair: The parameters have not been configured
19 correctly. See the Systems Operation Section,
“Programmable Parameters” section of this
SMCS Code: 7610-038-DTN manual.
Conditions Which Generate This Code: STOP.
Test Step 2. CHECK THE ENGINE

CONTROL UNIT FOR ACTIVE
A. Check the Engine control unit for active diagnostic
trouble codes for the speed sensors.
Expected Result:
The Engine control unit has active diagnostic codes

for the speed sensors.
Results:
g01350167
Illustration 43
• OK – The Engine control unit has active diagnostic
codes.
This diagnostic code is recorded when the data for
the engine torque is not available on the J1939 Data Repair: Perform the procedures for the speed
Link. The data link is not the cause of this diagnostic sensors. Verify that clearing the diagnostic trouble
trouble code. codes on the Engine control unit has corrected the
problem.
STOP.
KENR5099-06 73
• NOT OK – The Engine control unit does not have Test Step 1. INSPECT THE HARNESS
active diagnostic codes for the speed sensors. CONNECTIONS.
Repair: Contact your dealership for possible A. Turn the disconnect switch to the OFF position.
consultation with Caterpillar. This consultation may
greatly reduce repair time. B. Inspect all of the harness connections. Make sure
that the connectors are clean and tight.
STOP.
i02567086
Transmission, SPN 525 - FMI 9 D. Check the harness for signs of damage or
abrasion.
SMCS Code: 3065-038
E. Check the wires at the connector. Ensure that
Conditions Which Generate This Code: the wires are secured tightly into the connector.
Perform a 45 N (10 lb) pull test on each of the
F. Check the exposed wires at the connectors for

H. Check the connectors for dirty contacts or

corroded contacts.
I. Check each pin and each socket of the machine

Note: See Testing and Adjusting, “Electrical

Connector - Inspect” for more information.
g01257797 Expected Result:

Illustration 44
Schematic of the shifter on the J1939 Data Link The machine harness connectors are tight and free
of corrosion.
The diagnostic trouble code is associated with the
Transmission ECU. The FMI 9 means that the ECU Results:
is not receiving the expected information from the
shifter. No codes are active for the data link. • OK – The machine harness connectors are tight
and free of corrosion. Proceed to Test Step 2.
are listed: • NOT OK – The machine harness connectors are
in need of repair.
• Trouble with the machine harness
• Disconnected shifter machine harness.
• The ECU has failed. This is unlikely. STOP.
System Response: Test Step 2. CHECK IF THE DIAGNOSTIC

The transmission maintains the current gear. The
current gear is maintained until a valid request for a A. Inspect the harness connectors. Clean the
gear change is received. contacts of the harness connectors and check the
74 KENR5099-06
B. Perform a 45 N (10 lb) pull test on each of the i02605895

that the harness connectors are fully seated and SMCS Code: 4812-038; 7610-038-DTN
fastened. Conditions Which Generate This Code:

Expected Result:
Results:


g01257797
ECU. Prior to replacing an ECU, always contact Illustration 45
your dealership for possible consultation with Schematic of the J1939 Data Link
repair time. See Testing and Adjusting, “Electronic The diagnostic trouble code is associated with the
Control Unit - Replace”. Transmission ECU. The FMI 9 means that the ECU
is not receiving any of the expected information from
STOP. the data link.
• NO – The SPN 525 FMI 9 is not active. The The possible causes of this diagnostic trouble code
diagnostic trouble code does not exist at this time. are listed if only two ECUs cannot communicate:
caused by a poor electrical connection at one of • Loose harness connections
reconnected. Resume normal vehicle operation. • Open wires
STOP.
• Problems with the terminating resistors
• Wires that are shorted to ground
• Wires that are shorted to the battery
• Data link high wire is shorted to the data link low
wire
• High resistance across the Data Link

• Interference across the wires for the Data Link
• Incompatible Software
• Incorrect setup for parameters
• Failure of a smart device
KENR5099-06 75
The possible causes of this diagnostic trouble code Expected Result:

are listed if all of the ECUs cannot communicate:
• Problems with the terminating resistors of corrosion.
• Wires that are shorted to ground Results:
• Wires that are shorted to the battery • OK – The machine harness connectors are tight
and free of corrosion. Proceed to Test Step 2.
• Data Link high wire is shorted to the Data Link low
wire • NOT OK – The machine harness connectors are
in need of repair.
• Interference across the wires for the Data Link
Note: The high and the low wires of the data link machine harness.
have a positive voltage. One does not have a
negative voltage. The shield wire should not be used Proceed to Test Step 8.
as a ground wire when the voltage is measured.
Always use a clean, unpainted connection to the Test Step 2. CHECK THE VOLTAGE OF
frame ground. The Caterpillar Electronic Technician, THE DATA LINK.
Cat ET, may show a controller to be off-line. The
controller may not have been recognized by Cat A. Turn the keyswitch and the disconnect switch to
ET. Cycling the key and restarting the Cat ET may the ON position.
correct the problem.
B. At the ECU, use an electrical spoon to measure
Test Step 1. INSPECT THE HARNESS the voltage. One at a time, measure the voltage
CONNECTIONS. of connector contact J1-67, J1-68, and J1-69 to
frame ground.
Note: Do not use the shield wire as a ground.
B. Inspect all of the harness connections. Make sure
that the connectors are clean and tight. Table 31
J1-67 J1-68 J1-69
that all the seals are present and in place. 0.5V to 4.5V 0.5V to 4.5V 0V
D. Check the harness for signs of damage or Expected Result:

abrasion.
The shield wire does not have a voltage. A voltage
E. Check the wires at the connector. Ensure that on the shield wire means that there is a short to the
the wires are secured tightly into the connector. battery. The voltage of the wires for the Data Link
Perform a 45 N (10 lb) pull test on each of the is correct.
care not to pull the wire out of the connector. Results:
F. Check the exposed wires at the connectors for • OK – The voltage of the wires for the Data Link is
nicks or signs of abrasion. correct. Proceed to Test Step 3.
G. Check for moisture inside the connector. • NOT OK – The voltage is greater than 4.5 volts.
H. Check the connectors for dirty contacts or Repair: Repair the machine harness or replace
corroded contacts. the harness.
I. Check each pin and each socket of the machine Proceed to Test Step 8.
are properly installed. The contacts should mate • NOT OK – The voltage is less than 0.5 volts.
correctly when the two pieces of the connector Proceed to Test Step 3.
Test Step 3. CHECK FOR A SHORT TO
Note: See Testing and Adjusting, “Electrical GROUND.
Connector - Inspect” for more information.
A. Turn the keyswitch and the disconnect switch to
the OFF position.
76 KENR5099-06
B. Disconnect the J1 harness connector for the ECU. B. Disconnect wire (K900-YL) and wire (K990-GN)
Disconnect the harness connector for the shift from the ECU.
pad.
C. Measure the continuity of each wire individually.
C. Measure the resistance of wire (K900-YL) to an Use a jumper wire in order to connect to the other
unpainted frame ground. Measure the resistance end of the wire in question.
of wire (K990-GN) to an unpainted frame ground.
Expected Result:
Expected Result:
There is continuity from one end of the wire to the
The resistance measurement is greater than 5000 other end.
ohms.
Results:
Results:
• OK – There is continuity from one end of the wire
• OK – The resistance measurement is correct. to the other end. The wire is correct. Proceed to
Proceed to Test Step 5. Test Step 6.
• NOT OK – The resistance measurement is • NOT OK – There is not continuity from one end of
not correct. The wire with the low resistance the wire to the other end. The wire is not correct.
measurement is shorted to ground.
Repair: Repair the machine harness or replace the machine harness.
machine harness.
Proceed to Test Step 8.
Test Step 6. CHECK THE TERMINATING
Test Step 4. CHECK FOR A SHORT IN RESISTORS.
THE WIRES FOR THE DATA LINK.
Note: Two 120 Ohm resistors should be located on
A. The keyswitch and the disconnect switch remain the CAN Data Link. A resistance of 60 ohms should
in the OFF position. be found at any point on the data link. Terminating
resistors are not always used on data links. The
B. Disconnect the terminating resistors if the resistors resistance measurement should be greater than
are a part of the circuit. 5000 ohms if resistors are not intentionally a part of
the circuit.
C. Measure the continuity between the data link
wires. A. The keyswitch and the disconnect switch remain
in the OFF position.
Expected Result:
B. Use an electrical spoon in order to connect to the
The resistance measurement is greater than 5000 back of the connector for one of the terminating
ohms. resistors.
Results: C. Measure the resistance between the wires.
• OK – The resistance measurement is correct. Expected Result:

The resistance measurement is between 55 and 65
• NOT OK – The resistance measurement is not ohms.
correct. The wires for the data link are connected.
Results:
machine harness. • OK – The resistance measurement is correct.
Test Step 5. CHECK FOR AN OPEN IN approximately 120 ohms. One of the resistors is
THE WIRES FOR THE DATA LINK. not functioning properly.
A. The keyswitch and the disconnect switch remain

in the OFF position.
KENR5099-06 77
Repair: Ensure that the resistor is fully connected D. Turn the disconnect switch and the key start
to the data link. Replace the resistor if the resistor switch to the ON position.
has failed.
approximately 40 ohms. Expected Result:
Repair: There is more than two resistors on the The SPN 639 FMI 9 is active.
circuit for the data link. Remove the extra resistor.
Results:
Test Step 7. CHECK IF THE SHIELD WIRE diagnostic trouble code has not been corrected.
IS SHORTED TO GROUND.
A. The keyswitch and the disconnect switch remain that the ECU has failed. Exit this procedure and
in the OFF position. perform this procedure again. If the cause of the
B. Remove the shield wire (A249-BK) from the ECU. Prior to replacing an ECU, always contact
connector harness at the ECU for every ECU. your dealership for possible consultation with
C. Use a multimeter in order to measure the repair time. See Testing and Adjusting, “Electronic
resistance of wire (A249-BK) to an unpainted Control Unit - Replace”.
machine ground.
STOP.
Expected Result:
The resistance measurement is greater than 5000 diagnostic trouble code does not exist at this time.
ohms. The initial diagnostic trouble code was probably
Results: the harness connectors that was disconnected and
• OK – The resistance measurement is greater than STOP.
5000 ohms. The circuit is correct. Proceed to Test
Step 8.
• NOT OK – The resistance is less than 5000 ohms.

The circuit is incorrect. The shield wire is shorted
to ground.

machine harness.



fastened.
78 KENR5099-06
i03019065 • Errors in the data link from other controls on the

data link
14 Note: There can be problems during attempts to
download data. The problems can come from an
SMCS Code: 4812-038; 7610-038-DTN ECU that requests a parameter when a flash program
is being attempted. The ECU may only service one of
Conditions Which Generate This Code: the requests. Problems can occur when an ECU is
expecting a parameter from another ECU that does
not support the message.
System Response:
The diagnostic trouble code remains active until

a power cycle has occurred and the requested
parameters have been received.
Note: Changing parameters or configurations might

require a power cycle. The power cycle clears
diagnostic trouble codes that are caused by missing
parameters or incompatible software. This can also
be managed in the design of the system. When
the parameters are changed, the ECU will request
the parameters again. The ECU then clears the
diagnostic trouble codes.
Test Step 1. VERIFY SOFTWARE

VERSION.
g01257797 Note: Check and record the latest software version

Illustration 46
for the machine electronic controls that is available
Schematic of the J1939 Data Link in SIS or on the CD.
The diagnostic trouble code is associated with the A. Verify that the Transmission ECU has the correct,
Transmission ECU. The FMI 14 means that the ECU most current software.
is not receiving the proper information from the data
link. B. Verify that every ECU has the correct, most
current software.
Note: Ensure that all of the electronic control units
are powered and that the wiring for the J1939 data Expected Result:
link is properly connected. This diagnostic trouble
code will become active when the Transmission ECU All of the software is up current.
is powered and the Engine ECM is not powered.
Results:
are listed: • OK – All of the software is current. STOP.
• Incompatible software or missing parameters from • NOT OK – The software is not current.
a message
Repair: Flash all controls with the latest software
• Requests of complete parameter is missing. release. Refer to Testing and Adjusting, “Electronic
Control Unit - Flash Program”. The diagnostic
• Expecting parameters from features that are not trouble code is no longer active.
enabled
STOP.
• Problems with the data link during ECU flash
programming. Test Step 2. INSPECT THE HARNESS
CONNECTIONS.
• The incorrect flash program was performed.
A. Turn the disconnect switch and the keyswitch to
• Problems with the data link during downloads of the OFF position.
data
KENR5099-06 79
B. Inspect all of the harness connections. Make sure Expected Result:

that the connections of the connectors are clean
and tight. Parameters are enabled for functions that are not
available on the transmission.
that all of the seals are present and in place. Results:
D. Check the harness for signs of damage or • OK – Parameters are enabled for functions that
abrasion. are not available on the transmission.
E. Check the wires at the connector. Ensure that Repair: Disable the parameters that are not
the wires are secured tightly into the connector. available. Turn the key start switch to the OFF
Perform a 45 N (10 lb) pull test on each of the position. Turn the key start switch to the ON
wires that are associated with the circuit. Take position.
F. Check the exposed portion of the wire at the
connector for nicks or signs of abrasion. • NOT OK – The parameters that are enabled for the
transmission are correct. Proceed to Test Step 4.
G. Check for moisture that is inside of the connector.
H. Check connectors for dirty contacts or corroded TROUBLE CODE REMAINS.
contacts.
I. Check each pin and each socket of the machine contacts of the harness connectors and check the
harness connector. Ensure that the contacts are wires for damage to the insulation that is caused
properly installed. The contacts should mate by excessive heat, battery acid, or chafing.
are placed together. B. Perform a 45 N (10 lb) pull test on each of the
Note: See the Testing and Adjusting, “Electrical
Connector - Inspect” section of this manual for more C. Reconnect all harness connectors. Make sure
information. that the harness connectors are fully seated and
Expected Result: fastened.
The machine harness connectors are connected D. Turn the disconnect switch and the key start
properly. The connectors are free of corrosion. switch to the ON position.
Results: E. Operate the vehicle.
• OK – The harness connections are correct. F. Check the status of the SPN 639 FMI 14.
Expected Result:
• NOT OK – The harness connections need to be
repaired. The SPN 639 FMI 14 is active.
Repair: Repair the machine harness or replace the Results:

machine harness.
STOP. diagnostic trouble code has not been corrected.
Test Step 3. CHECK THE ENABLED Repair: Check the circuit again. It is unlikely
PARAMETERS FOR THE MACHINE. that the ECU has failed. Exit this procedure and
A. Turn the disconnect switch and the key start diagnostic trouble code is not found, replace the
switch to the ON position. ECU. Prior to replacing an ECU, always contact
B. Use the Caterpillar Electronic Technician (ET) in Caterpillar. This consultation may greatly reduce
order to view all of the enabled parameters. repair time. See Testing and Adjusting, “Electronic
STOP.
80 KENR5099-06
• NO – The SPN 639 FMI 14 is not active. The Test Step 1. CHECK THE ENERGIZE
diagnostic trouble code does not exist at this time. CIRCUIT OF THE SOLENOID FOR A
The initial diagnostic trouble code was probably SHORT TO THE +BATTERY CIRCUIT.
the harness connectors that was disconnected and A. Turn the key start switch and the disconnect
reconnected. Resume normal vehicle operation. switch to the OFF position.
STOP.
B. Disconnect the machine harness connectors from
the solenoid and the ECU.
i02520200
Transmission, SPN 734 - FMI 3 C. At the machine harness connector for the ECU,
measure the resistance from contact J1-59 (wire
SMCS Code: 3139-038-T3 751-GN) to all contacts that are used in the
machine harness connectors for the ECU.
Expected Result:
Each resistance measurement is greater than 5000

ohms.
Results:
• OK – Each resistance measurement is greater

than 5000 ohms. The machine harness is correct.
• NOT OK – Each resistance measurement is not

greater than 5000 ohms. There is a short in the
machine harness. The short is between J1-59
(751-GN) and the circuit that has a low resistance
g01238990 measurement.
Illustration 47
Schematic of the transmission shift solenoid 1
This diagnostic trouble code is associated with the machine harness.
transmission solenoid valve 1. The FMI “3” means
that the ECU has determined that the voltage of the STOP.
solenoid circuit is above normal.
The possible causes of the diagnostic trouble code TROUBLE CODE IS STILL ACTIVE.
are listed:
• The solenoid has failed. contacts of the harness connectors and check the
• The energize circuit of the solenoid is shorted to by excessive heat, battery acid, or chafing.
the +battery circuit.
• The ECU has failed. This is unlikely. wires that are associated with the circuit.
Note: The following test procedure may create C. Reconnect all harness connectors in order to
other diagnostic trouble codes. Ignore these make sure that the connectors are fully seated.
created diagnostic trouble codes and clear these Also, make sure that the clips for each connector
diagnostic trouble codes when the original diagnostic are completely fastened.
diagnostic trouble code of SPN 734 FMI 3 is D. Turn the disconnect switch and the key start
active before performing this procedure. switch to the ON position.
Note: Use a digital multimeter for the measurements E. Operate the machine.
in this procedure.
System Response:
Expected Result:
Only gears that are engaged by the solenoid are
available. The lockup clutch is turned OFF. The SPN 734 FMI 3 is active.
KENR5099-06 81
Results: • The ECU has failed. This is unlikely.

• YES – The SPN 734 FMI 3 is active. The Note: The following test procedure may create
diagnostic trouble code has not been corrected. other diagnostic trouble codes. Ignore these
Repair: Check the circuit again. It is unlikely diagnostic trouble codes when the original diagnostic
that the ECU has failed. Exit this procedure and trouble code has been corrected. Ensure that the
perform this procedure again. If the cause of the diagnostic trouble code of SPN 734 FMI 5 is
diagnostic trouble code is not found, replace the active before performing this procedure.
your dealership for possible consultation with Note: Use a digital multimeter for the measurements
Caterpillar. This consultation may greatly reduce in this procedure.
Control Unit - Replace”. System Response:
STOP. All gears that are engaged by the solenoid are

unavailable. The lockup clutch is turned OFF.
diagnostic trouble code does not exist at this time. Test Step 1. CHECK THE SOLENOID.
caused by a poor electrical connection or a A. Turn the disconnect switch and the key start
short at one of the harness connectors that was switch to the ON position. Do not start the engine.
machine operation. STOP. B. Disconnect the solenoid with the active diagnostic
trouble code from the machine harness.
i02480845
Transmission, SPN 734 - FMI 5 solenoid, place a jumper wire from contact 1 (wire
751-GN) to contact 2 (wire 921-WH).
SMCS Code: 3139-038-T3
D. Observe the status of the SPN 734 FMI 5.
Expected Result:
The diagnostic trouble code is active. Then, the

diagnostic trouble code changes from FMI 5 to FMI 6
as the jumper wire is installed.
Results:

The jumper wire does not affect the diagnostic
trouble code. Proceed to Test Step 2.
• NO – The diagnostic is no longer active. The

solenoid has failed.
Illustration 48
g01238990 Repair: The solenoid has failed. Replace the
Schematic of the transmission shift solenoid 1 solenoid. Verify that the new solenoid corrects the
problem.
transmission solenoid valve 1. The FMI “5” means STOP.
that the ECU has determined that an open in the
circuit exists. Test Step 2. CHECK THE HARNESS FOR
AN OPEN.
are listed below: A. Turn the key start switch and the disconnect
• The energize circuit of the solenoid is open.
B. Disconnect the machine harness connector(s)
• The return circuit of the solenoid is open. from the ECU.
• The solenoid has failed.

82 KENR5099-06
C. The jumper wire that was installed in the previous Repair: Check the circuit again. If the Caterpillar
Test Step remains in place. Electronic Technician (ET) is available, use the Cat
ET service tool in order to perform a “Wiggle Test”
D. At the machine harness connector, measure on the machine wiring harness. The “Wiggle Test”
the resistance from signal contact J1-59 (wire can detect shorts and opens in the machine wiring
751-GN) to contact J1-60 (wire 921-WH). harness that are momentary or intermittent.
Expected Result: It is unlikely that the ECU has failed. Exit this
The resistance is less than 5.0 ohms. the cause of the diagnostic trouble code is not
found, replace the ECU. Prior to replacing an
Results: ECM, always contact your dealership for possible
• OK – The resistance is less than 5.0 ohms. The may greatly reduce repair time. See Testing and
machine harness is correct. Proceed to Test Step Adjusting, “Electronic Control Unit - Replace”.
3.
STOP.
• NOT OK – The resistance is greater than 5000
ohms. The resistance measurement is not correct. • NO – The SPN 734 FMI 5 is not active. The
There is an open circuit in the machine harness. diagnostic trouble code does not exist at this time.
Repair: Repair the machine harness or replace the caused by a poor electrical connection or a
machine harness. short at one of the harness connectors that was
STOP. machine operation. STOP.

TROUBLE CODE REMAINS. i02480846

contacts of the harness connectors and check the SMCS Code: 3139-038-T3
by excessive heat, battery acid, or chafing. Conditions Which Generate This Code:

fastened.


g01238990
Illustration 49
Expected Result: Schematic of the transmission shift solenoid 1
The SPN 734 FMI 5 is active. This diagnostic trouble code is associated with the
solenoid valve 1. The FMI 6 means that the ECU
Results: has determined that there is a short to ground in the
solenoid circuit.
diagnostic trouble code has not been corrected. The possible causes of this diagnostic trouble code
are listed:
• The energize circuit of the solenoid is shorted to

ground.

KENR5099-06 83
• The ECU has failed. This is unlikely. D. At the machine harness connector, measure the
resistance from the signal contact J1-59 (wire
Note: The following test procedure may create 751-GN) to all contacts that are used in the
other diagnostic trouble codes. Ignore these machine harness connectors for the ECU.
diagnostic trouble codes when the original diagnostic Expected Result:
diagnostic trouble code of SPN 734 FMI 6 is Each resistance measurement is greater than 5000
active before performing this procedure. ohms.
Note: Use a digital multimeter for the measurements Results:

in this procedure.
System Response: than 5000 ohms. The machine harness is correct.
All gears that are engaged by the solenoid are
unavailable. The lockup clutch is turned OFF. • NOT OK – Each resistance measurement is not
Test Step 1. CHECK THE SOLENOID. machine harness. The short is between J1-59 (wire
751-GN) and the circuit with the low resistance
A. Turn the disconnect switch and the key start measurement.
switch to the ON position. Do not start the engine.
B. Observe the status of the diagnostic trouble code. machine harness.
C. Disconnect the solenoid with the active diagnostic STOP.

Expected Result: TROUBLE CODE REMAINS.
The FMI 6 changes to FMI 5 when the solenoid is A. Inspect the harness connectors. Clean the
disconnected. contacts of the harness connectors and check the
Results: by excessive heat, battery acid, or chafing.
• YES – The FMI 6 changes to FMI 5 when the B. Perform a 45 N (10 lb) pull test on each of the
solenoid is disconnected. The circuit is correct. wires that are associated with the circuit.
Repair: The solenoid has failed. Replace the C. Reconnect all harness connectors. Make sure
solenoid. Verify that the new solenoid corrects the that the harness connectors are fully seated and
problem. that the clips for each connector are completely
fastened.
STOP.
• NO – The SPN 734 FMI 6 remains active. Proceed switch to the ON position.
to Test Step 2.
Test Step 2. CHECK THE ENERGIZE
CIRCUIT OF THE SOLENOID FOR A F. Check the status of the SPN 734 FMI 6.
SHORT TO GROUND.
Expected Result:
A. Turn the key start switch and the disconnect
switch to the OFF position. The SPN 734 FMI 6 is active.
B. The solenoid remains disconnected from the Results:

machine harness.
C. Disconnect the machine harness connector(s) diagnostic trouble code has not been corrected.
from the ECU.
84 KENR5099-06
Repair: Check the circuit again. If the Caterpillar • The ECU has failed. This is unlikely.
Electronic Technician (ET) is available, use the Cat
ET service tool in order to perform a “Wiggle Test” Note: The following test procedure may create
on the machine wiring harness. The “Wiggle Test” other diagnostic trouble codes. Ignore these
can detect shorts and opens in the machine wiring created diagnostic trouble codes and clear these
harness that are momentary or intermittent. diagnostic trouble codes when the original diagnostic
It is unlikely that the ECU has failed. Exit this diagnostic trouble code of SPN 735 FMI 3 is
procedure and perform this procedure again. If active before performing this procedure.
the cause of the diagnostic trouble code is not
found, replace the ECU. Prior to replacing an Note: Use a digital multimeter for the measurements
ECM, always contact your dealership for possible in this procedure.
may greatly reduce repair time. See Testing and System Response:
STOP. available. The lockup clutch is turned OFF.
the harness connectors that was disconnected and A. Turn the key start switch and the disconnect
reconnected. Resume normal machine operation. switch to the OFF position.
STOP.
i02520448
Transmission, SPN 735 - FMI 3 C. At the machine harness connector for the ECU,
measure the resistance from contact J1-49
SMCS Code: 3139-038-T3 (wire 752-YL) to all contacts that are used in the
Expected Result:

ohms.
Results:


(752-YL) and the circuit that has a low resistance
g01238998 measurement.
Illustration 50
Schematic of the transmission solenoid valve 2
This diagnostic trouble code is associated with the machine harness.
transmission solenoid valve 2. The FMI 3 means
that the ECU has determined that the voltage of the STOP.
The possible causes of the diagnostic trouble code TROUBLE CODE IS STILL ACTIVE.
are listed:
• The solenoid has failed. contacts of the harness connectors and check the
• The energize circuit of the solenoid is shorted to by excessive heat, battery acid, or chafing.
KENR5099-06 85
B. Perform a 45 N (10 lb) pull test on each of the i02480857

make sure that the connectors are fully seated. SMCS Code: 3139-038-T3
are completely fastened. Conditions Which Generate This Code:

Expected Result:
Results:
• YES – The SPN 735 FMI 3 is active. The Illustration 51

g01238998
that the ECU has failed. Exit this procedure and This diagnostic trouble code is associated with the
perform this procedure again. If the cause of the transmission solenoid valve 2. The FMI 5 means that
diagnostic trouble code is not found, replace the the ECU has determined that an open in the circuit
ECU. Prior to replacing an ECU, always contact exists.
Caterpillar. This consultation may greatly reduce The possible causes of this diagnostic trouble code
repair time. See Testing and Adjusting, “Electronic are listed below:
STOP.
• The return circuit of the solenoid is open.
diagnostic trouble code does not exist at this time. • The solenoid has failed.
caused by a poor electrical connection or a • The ECU has failed. This is unlikely.
disconnected and reconnected. Resume normal Note: The following test procedure may create
machine operation. STOP. other diagnostic trouble codes. Ignore these

in this procedure.
System Response:

Test Step 1. CHECK THE SOLENOID.

86 KENR5099-06
B. Disconnect the solenoid with the active diagnostic Repair: Repair the machine harness or replace the
trouble code from the machine harness. machine harness.
C. At the machine harness connector for the STOP.

solenoid, place a jumper wire from contact 1 (wire
752-YL) to contact 2 (wire 922-BR). Test Step 3. CHECK IF THE DIAGNOSTIC
Expected Result: contacts of the harness connectors and check the
The diagnostic trouble code is active. Then, the by excessive heat, battery acid, or chafing.
as the jumper wire is installed. B. Perform a 45 N (10 lb) pull test on each of the
Results:
• YES – The diagnostic trouble code remains active. that the harness connectors are fully seated and
The jumper wire does not affect the diagnostic that the clips for each connector are completely
trouble code. Proceed to Test Step 2. fastened.
• NO – The diagnostic trouble code is no longer D. Turn the disconnect switch and the key start
active. The solenoid has failed. switch to the ON position.
Repair: The solenoid has failed. Replace the E. Operate the vehicle.
solenoid. Verify that the new solenoid corrects the
problem. F. Check the status of the SPN 735 FMI 5.
STOP. Expected Result:
Test Step 2. CHECK THE HARNESS FOR The SPN 735 FMI 5 is active.
AN OPEN.
Results:
switch to the OFF position. • YES – The SPN 735 FMI 5 is active. The
from the ECU. Repair: Check the circuit again. If the Caterpillar
C. The jumper wire that was installed in the previous ET service tool in order to perform a “Wiggle Test”
Test Step remains in place. on the machine wiring harness. The “Wiggle Test”
can detect shorts and opens in the machine wiring
D. At the machine harness connector, measure the harness that are momentary or intermittent.
resistance from signal contact J1-49 (wire 752-YL)
to contact J1-50 (wire 922-BR). It is unlikely that the ECU has failed. Exit this
Expected Result: the cause of the diagnostic trouble code is not
The resistance is less than 5.0 ohms. ECM, always contact your dealership for possible
Results: may greatly reduce repair time. See Testing and
• OK – The resistance is less than 5.0 ohms. The
machine harness is correct. Proceed to Test Step STOP.
3.
• NOT OK – The resistance is greater than 5000 diagnostic trouble code does not exist at this time.
ohms. The resistance measurement is not correct. The initial diagnostic trouble code was probably
There is an open circuit in the machine harness. caused by a poor electrical connection at one of
STOP.
KENR5099-06 87
i02480864 C. Disconnect the solenoid with the active diagnostic

Expected Result:
The FMI 6 changes to FMI 5 when the solenoid is
Conditions Which Generate This Code: disconnected.
Results:
• YES – The FMI 6 changes to FMI 5 when the

solenoid is disconnected. The circuit is correct.
Repair: The solenoid has failed. Replace the

problem.
STOP.
• NO – The SPN 735 FMI 6 remains active. Proceed

to Test Step 2.
g01238998
Illustration 52
CIRCUIT OF THE SOLENOID FOR A
SHORT TO GROUND.
transmission solenoid valve 2. The FMI 6 means A. Turn the key start switch and the disconnect
that the ECU has determined that there is a short to switch to the OFF position.
ground in the solenoid circuit.
B. The solenoid remains disconnected from the
The possible causes of this diagnostic trouble code machine harness.
are listed:
C. Disconnect the machine harness connector(s)
• The energize circuit of the solenoid is shorted to from the ECU.
ground.
D. At the machine harness connector, measure
• The solenoid has failed. the resistance from the signal contact J1-49
(wire 752-YL) to all contacts that are used in the
• The ECU has failed. This is unlikely. machine harness connectors for the ECU.
Note: The following test procedure may create Expected Result:
created diagnostic trouble codes and clear these Each resistance measurement is greater than 5000
diagnostic trouble codes when the original diagnostic ohms.
diagnostic trouble code of SPN 735 FMI 6 is Results:

System Response:
All gears that are engaged by the solenoid are machine harness. The short is between J1-49 (wire
unavailable. The lockup clutch is turned OFF. 752-YL) and the circuit with the low resistance
measurement.
A. Turn the disconnect switch and the key start machine harness.
STOP.
88 KENR5099-06
Test Step 3. CHECK IF THE DIAGNOSTIC i02520762

contacts of the harness connectors and check the SMCS Code: 3139-038-T3
by excessive heat, battery acid, or chafing. Conditions Which Generate This Code:


fastened.

F. Check the status of the SPN 735 FMI 6. g01239000

Illustration 53
Expected Result:
The SPN 735 FMI 6 is active. This diagnostic trouble code is associated with the
Results: that the ECU has determined that the voltage of the
• YES – The SPN 735 FMI 6 is active. The The possible causes of the diagnostic trouble code
are listed:
Repair: Check the circuit again. If the Caterpillar
Electronic Technician (ET) is available, use the Cat • The solenoid has failed.
on the machine wiring harness. The “Wiggle Test” • The energize circuit of the solenoid is shorted to
can detect shorts and opens in the machine wiring the +battery circuit.
harness that are momentary or intermittent.
It is unlikely that the ECU has failed. Exit this
procedure and perform this procedure again. If Note: The following test procedure may create
the cause of the diagnostic trouble code is not other diagnostic trouble codes. Ignore these
found, replace the ECU. Prior to replacing an created diagnostic trouble codes and clear these
ECM, always contact your dealership for possible diagnostic trouble codes when the original diagnostic
consultation with Caterpillar. This consultation trouble code has been corrected. Ensure that the
may greatly reduce repair time. See Testing and diagnostic trouble code of SPN 736 FMI 3 is
Adjusting, “Electronic Control Unit - Replace”. active before performing this procedure.
STOP. Note: Use a digital multimeter for the measurements

in this procedure.
• NO – The SPN 735 FMI 6 is not active. The System Response:
caused by a poor electrical connection or a Only gears that are engaged by the solenoid are
short at one of the harness connectors that was available. The lockup clutch is turned OFF.
vehicle operation. STOP. Test Step 1. CHECK THE ENERGIZE
SHORT TO THE +BATTERY CIRCUIT.
KENR5099-06 89
B. Disconnect the machine harness connectors from Repair: Check the circuit again. It is unlikely
the solenoid and the ECU. that the ECU has failed. Exit this procedure and
C. At the machine harness connector for the ECU, diagnostic trouble code is not found, replace the
measure the resistance from contact J1-51 (wire ECU. Prior to replacing an ECU, always contact
754-BU) to all contacts that are used in the your dealership for possible consultation with
machine harness connectors for the ECU. Caterpillar. This consultation may greatly reduce
Expected Result: Control Unit - Replace”.
Each resistance measurement is greater than 5000 STOP.

ohms.
Results: diagnostic trouble code does not exist at this time.
• OK – Each resistance measurement is greater caused by a poor electrical connection or a
than 5000 ohms. The machine harness is correct. short at one of the harness connectors that was
Proceed to Test Step 2. disconnected and reconnected. Resume normal
i02480859
(754-BU) and the circuit that has a low resistance
measurement.
machine harness. Conditions Which Generate This Code:
STOP.



make sure that the connectors are fully seated. g01239000
Illustration 54
Also, make sure that the clips for each connector Schematic of the transmission shift solenoid 3
D. Turn the disconnect switch and the key start transmission shift solenoid valve 3. The FMI 5 means
switch to the ON position. that the ECU has determined that an open in the
circuit exists.
F. Determine if the SPN 736 FMI 3 is active. are listed below:
Expected Result: • The energize circuit of the solenoid is open.
The SPN 736 FMI 3 is active. • The return circuit of the solenoid is open.
Results: • The solenoid has failed.
• YES – The SPN 736 FMI 3 is active. The • The ECU has failed. This is unlikely.
90 KENR5099-06
Note: The following test procedure may create D. At the machine harness connector, measure
other diagnostic trouble codes. Ignore these the resistance from signal contact J1-51 (wire
created diagnostic trouble codes and clear these 754-BU) to contact J1-50 (wire 922-BR).
trouble code has been corrected. Ensure that the Expected Result:
active before performing this procedure. The resistance is less than 5.0 ohms.

in this procedure.
System Response: machine harness is correct. Proceed to Test Step
3.
unavailable. The lockup clutch is turned OFF. • NOT OK – The resistance is greater than 5000
ohms. The resistance measurement is not correct.
Test Step 1. CHECK THE SOLENOID. There is an open circuit in the machine harness.
A. Turn the disconnect switch and the key start Repair: Repair the machine harness or replace the
switch to the ON position. Do not start the engine. machine harness.
B. Disconnect the solenoid with the active diagnostic STOP.

C. At the machine harness connector for the TROUBLE CODE REMAINS.
754-BU) to contact 2 (wire 922-BR). A. Inspect the harness connectors. Clean the
D. Observe the status of the SPN 736 FMI 5. wires for damage to the insulation that is caused
Expected Result:
The diagnostic trouble code is active. Then, the wires that are associated with the circuit.
as the jumper wire is installed. C. Reconnect all harness connectors. Make sure
Results: that the clips for each connector are completely
fastened.
The jumper wire does not affect the diagnostic D. Turn the disconnect switch and the key start
trouble code. Proceed to Test Step 2. switch to the ON position.
• NO – The diagnostic trouble code is no longer E. Operate the vehicle.

active. The solenoid has failed.
solenoid. Verify that the new solenoid corrects the Expected Result:
problem.
STOP.
Results:
AN OPEN. • YES – The SPN 736 FMI 5 is active. The
switch to the OFF position. Repair: Check the circuit again. If the Caterpillar
B. Disconnect the machine harness connector(s) ET service tool in order to perform a “Wiggle Test”
from the ECU. on the machine wiring harness. The “Wiggle Test”
C. The jumper wire that was installed in the previous harness that are momentary or intermittent.
Test Step remains in place.
KENR5099-06 91
It is unlikely that the ECU has failed. Exit this Note: The following test procedure may create
procedure and perform this procedure again. If other diagnostic trouble codes. Ignore these
the cause of the diagnostic trouble code is not created diagnostic trouble codes and clear these
found, replace the ECU. Prior to replacing an diagnostic trouble codes when the original diagnostic
ECM, always contact your dealership for possible trouble code has been corrected. Ensure that the
consultation with Caterpillar. This consultation diagnostic trouble code of SPN 736 FMI 6 is
may greatly reduce repair time. See Testing and active before performing this procedure.
STOP. in this procedure.

Repair: The initial diagnostic trouble code was unavailable. The lockup clutch is turned OFF.
probably caused by a poor electrical connection
at one of the harness connectors that was Test Step 1. CHECK THE SOLENOID.
vehicle operation. A. Turn the disconnect switch and the key start
STOP.
i02480866
C. Disconnect the solenoid with the active diagnostic
Transmission, SPN 736 - FMI 6 trouble code from the machine harness.
SMCS Code: 3139-038-T3 Expected Result:
Conditions Which Generate This Code: The FMI 6 changes to FMI 5 when the solenoid is
disconnected.
Results:


problem.
STOP.

to Test Step 2.
g01239000
Illustration 55
Schematic of the transmission shift solenoid 3 Test Step 2. CHECK THE ENERGIZE
This diagnostic trouble code is associated with the SHORT TO GROUND.
that the ECU has determined that there is a short to A. Turn the key start switch and the disconnect
ground in the solenoid circuit. switch to the OFF position.
The possible causes of this diagnostic trouble code B. The solenoid remains disconnected from the
are listed: machine harness.
• The energize circuit of the solenoid is shorted to C. Disconnect the machine harness connector(s)
ground. from the ECU.
• The solenoid has failed. D. At the machine harness connector, measure the
• The ECU has failed. This is unlikely. 754-BU) to all contacts that are used in the
92 KENR5099-06
Each resistance measurement is greater than 5000 the cause of the diagnostic trouble code is not
ohms. found, replace the ECU. Prior to replacing an
Results: consultation with Caterpillar. This consultation
• OK – Each resistance measurement is greater Adjusting, “Electronic Control Unit - Replace”.
Proceed to Test Step 3. STOP.
• NOT OK – Each resistance measurement is not • NO – The SPN 736 FMI 6 is not active. The
greater than 5000 ohms. There is a short in the diagnostic trouble code does not exist at this time.
machine harness. The short is between J1-51 (wire The initial diagnostic trouble code was probably
754-BU) and the circuit with the low resistance caused by a poor electrical connection or a
measurement. short at one of the harness connectors that was
Repair: Repair the machine harness or replace the vehicle operation. STOP.
machine harness.
i02520769
STOP.

TROUBLE CODE REMAINS. SMCS Code: 3139-038-T3
A. Inspect the harness connectors. Clean the Conditions Which Generate This Code:


fastened.

E. Operate the vehicle. g01239001

Illustration 56
Expected Result: transmission solenoid valve 4. The FMI 3 means
that the ECU has determined that the voltage of the
The SPN 736 FMI 6 is active. solenoid circuit is above normal.
Results: The possible causes of the diagnostic trouble code
are listed:
diagnostic trouble code has not been corrected. • The solenoid has failed.
Repair: Check the circuit again. If the Caterpillar • The energize circuit of the solenoid is shorted to
Electronic Technician (ET) is available, use the Cat the +battery circuit.
on the machine wiring harness. The “Wiggle Test” • The ECU has failed. This is unlikely.
KENR5099-06 93
Note: The following test procedure may create C. Reconnect all harness connectors in order to
other diagnostic trouble codes. Ignore these make sure that the connectors are fully seated.
created diagnostic trouble codes and clear these Also, make sure that the clips for each connector
diagnostic trouble codes when the original diagnostic are completely fastened.
diagnostic trouble code of SPN 737 FMI 3 is D. Turn the disconnect switch and the key start
active before performing this procedure. switch to the ON position.
Note: Use a digital multimeter for the measurements E. Operate the machine.
in this procedure.
System Response:
Expected Result:
available. The lockup clutch is turned OFF. The SPN 737 FMI 3 is active.
Test Step 1. CHECK THE ENERGIZE Results:

SHORT TO THE +BATTERY CIRCUIT. • YES – The SPN 737 FMI 3 is active. The
switch to the OFF position. Repair: Check the circuit again. It is unlikely
B. Disconnect the machine harness connectors from perform this procedure again. If the cause of the
the solenoid and the ECU. diagnostic trouble code is not found, replace the
C. At the machine harness connector for the ECU, your dealership for possible consultation with
measure the resistance from contact J1-52 (wire Caterpillar. This consultation may greatly reduce
755-OR) to all contacts that are used in the repair time. See Testing and Adjusting, “Electronic
machine harness connectors for the ECU. Control Unit - Replace”.
Each resistance measurement is greater than 5000 • NO – The SPN 737 FMI 3 is not active. The
ohms. diagnostic trouble code does not exist at this time.
Results: caused by a poor electrical connection or a
• OK – Each resistance measurement is greater disconnected and reconnected. Resume normal
than 5000 ohms. The machine harness is correct. machine operation. STOP.

(755-OR) and the circuit that has a low resistance
measurement.

machine harness.
STOP.


94 KENR5099-06
i02480861 B. Disconnect the solenoid with the active diagnostic

SMCS Code: 3139-038-T3 solenoid, place a jumper wire from contact 1 (wire
755-OR) to contact 2 (wire 922-BR).
Expected Result:

Results:

Illustration 57
g01239001 • NO – The diagnostic is no longer active. The
This diagnostic trouble code is associated with the solenoid. Verify that the new solenoid corrects the
transmission solenoid valve 4. The FMI 5 means that problem.
the ECU has determined that an open in the circuit
exists. STOP.
The possible causes of this diagnostic trouble code Test Step 2. CHECK THE HARNESS FOR
are listed below: AN OPEN.
• The energize circuit of the solenoid is open. A. Turn the key start switch and the disconnect
• The solenoid has failed. from the ECU.
• The ECU has failed. This is unlikely. C. The jumper wire that was installed in the previous
other diagnostic trouble codes. Ignore these D. At the machine harness connector, measure
created diagnostic trouble codes and clear these the resistance from signal contact J1-52 (wire
diagnostic trouble codes when the original diagnostic 755-OR) to contact J1-50 (wire 922-BR).
diagnostic trouble code of SPN 737 FMI 5 is Expected Result:
The resistance is less than 5.0 ohms.
in this procedure. Results:
System Response:
machine harness is correct. Proceed to Test Step
All gears that are engaged by the solenoid are 3.
Test Step 1. CHECK THE SOLENOID. • NOT OK – The resistance is greater than 5000
There is an open circuit in the machine harness.
KENR5099-06 95
Repair: Repair the machine harness or replace the Repair: The initial diagnostic trouble code was
machine harness. probably caused by a poor electrical connection
at one of the harness connectors that was
STOP. disconnected and reconnected. Resume normal
vehicle operation.
TROUBLE CODE REMAINS. STOP.

i02480869
wires that are associated with the circuit. Conditions Which Generate This Code:
fastened.

Expected Result:
The SPN 737 FMI 5 is active. g01239001

Illustration 58
Results:
• YES – The SPN 737 FMI 5 is active. The transmission solenoid valve 4. The FMI 6 means
diagnostic trouble code has not been corrected. that the ECU has determined that there is a short to
Electronic Technician (ET) is available, use the Cat The possible causes of this diagnostic trouble code
ET service tool in order to perform a “Wiggle Test” are listed:
on the machine wiring harness. The “Wiggle Test”
can detect shorts and opens in the machine wiring • The energize circuit of the solenoid is shorted to
harness that are momentary or intermittent. ground.
It is unlikely that the ECU has failed. Exit this • The solenoid has failed.
the cause of the diagnostic trouble code is not • The ECU has failed. This is unlikely.
ECM, always contact your dealership for possible Note: The following test procedure may create
consultation with Caterpillar. This consultation other diagnostic trouble codes. Ignore these
may greatly reduce repair time. See Testing and created diagnostic trouble codes and clear these
Adjusting, “Electronic Control Unit - Replace”. diagnostic trouble codes when the original diagnostic
STOP. diagnostic trouble code of SPN 737 FMI 6 is
diagnostic trouble code does not exist at this time. Note: Use a digital multimeter for the measurements
in this procedure.
System Response:

96 KENR5099-06
Test Step 1. CHECK THE SOLENOID. Repair: Repair the machine harness or replace the
machine harness.
switch to the ON position. Do not start the engine. STOP.
B. Observe the status of the diagnostic trouble code. Test Step 3. CHECK IF THE DIAGNOSTIC
trouble code from the machine harness. A. Inspect the harness connectors. Clean the
Expected Result: wires for damage to the insulation that is caused
disconnected. B. Perform a 45 N (10 lb) pull test on each of the
Results:
• YES – The FMI 6 changes to FMI 5 when the that the harness connectors are fully seated and
solenoid is disconnected. The circuit is correct. that the clips for each connector are completely
fastened.
solenoid. Verify that the new solenoid corrects the D. Turn the disconnect switch and the key start
problem. switch to the ON position.
STOP. E. Operate the vehicle.
• NO – The SPN 737 FMI 6 remains active. Proceed F. Check the status of the SPN 737 FMI 6.
to Test Step 2.
Expected Result:
CIRCUIT OF THE SOLENOID FOR A The SPN 737 FMI 6 is active.
SHORT TO GROUND.
Results:
machine harness. Repair: Check the circuit again. If the Caterpillar
C. Disconnect the machine harness connector(s) ET service tool in order to perform a “Wiggle Test”
from the ECU. on the machine wiring harness. The “Wiggle Test”
D. At the machine harness connector, measure the harness that are momentary or intermittent.
755-OR) to all contacts that are used in the It is unlikely that the ECU has failed. Exit this
machine harness connectors for the ECU. procedure and perform this procedure again. If
Expected Result: found, replace the ECU. Prior to replacing an
Each resistance measurement is greater than 5000 consultation with Caterpillar. This consultation
ohms. may greatly reduce repair time. See Testing and
Results:
STOP.
than 5000 ohms. The machine harness is correct. • NO – The SPN 737 FMI 6 is not active. The
Proceed to Test Step 3. diagnostic trouble code does not exist at this time.
• NOT OK – Each resistance measurement is not caused by a poor electrical connection or a
greater than 5000 ohms. There is a short in the short at one of the harness connectors that was
machine harness. The short is between J1-52 (wire disconnected and reconnected. Resume normal
755-OR) and the circuit with the low resistance vehicle operation. STOP.
measurement.
KENR5099-06 97
i02520772 B. Disconnect the machine harness connectors from

C. At the machine harness connector for the ECU,
SMCS Code: 3139-038-T3 measure the resistance from contact J1-58 (wire
921-WH) to all contacts that are used in the
Conditions Which Generate This Code: machine harness connectors for the ECU.
Expected Result:

ohms.
Results:


g01239004 machine harness. The short is between J1-58
Illustration 59
(921-WH) and the circuit that has a low resistance
Schematic of the transmission shift solenoid 5 measurement.
This diagnostic trouble code is associated with the Repair: Repair the machine harness or replace the
transmission solenoid valve 5. The FMI 3 means machine harness.
that the ECU has determined that the voltage of the
solenoid circuit is above normal. STOP.
The possible causes of the diagnostic trouble code Test Step 2. CHECK IF THE DIAGNOSTIC
are listed: TROUBLE CODE IS STILL ACTIVE.
• The solenoid has failed. A. Inspect the harness connectors. Clean the
• The energize circuit of the solenoid is shorted to wires for damage to the insulation that is caused
the +battery circuit. by excessive heat, battery acid, or chafing.
• The ECU has failed. This is unlikely. B. Perform a 45 N (10 lb) pull test on each of the
other diagnostic trouble codes. Ignore these C. Reconnect all harness connectors in order to
created diagnostic trouble codes and clear these make sure that the connectors are fully seated.
diagnostic trouble codes when the original diagnostic Also, make sure that the clips for each connector
trouble code has been corrected. Ensure that the are completely fastened.
active before performing this procedure. D. Turn the disconnect switch and the key start
in this procedure. E. Operate the machine.
System Response: F. Determine if the SPN 738 FMI 3 is active.
Only gears that are engaged by the solenoid are Expected Result:
available. The lockup clutch is turned OFF.
CIRCUIT OF THE SOLENOID FOR A Results:
A. Turn the key start switch and the disconnect diagnostic trouble code has not been corrected.
98 KENR5099-06
Repair: Check the circuit again. It is unlikely Note: The following test procedure may create
that the ECU has failed. Exit this procedure and other diagnostic trouble codes. Ignore these
perform this procedure again. If the cause of the created diagnostic trouble codes and clear these
diagnostic trouble code is not found, replace the diagnostic trouble codes when the original diagnostic
ECU. Prior to replacing an ECU, always contact trouble code has been corrected. Ensure that the
your dealership for possible consultation with diagnostic trouble code of SPN 738 FMI 5 is
Caterpillar. This consultation may greatly reduce active before performing this procedure.
Control Unit - Replace”. Note: Use a digital multimeter for the measurements
in this procedure.
STOP.
System Response:
diagnostic trouble code does not exist at this time. All gears that are engaged by the solenoid are
The initial diagnostic trouble code was probably unavailable. The lockup clutch is turned OFF.
short at one of the harness connectors that was Test Step 1. CHECK THE SOLENOID.
machine operation. STOP. A. Turn the disconnect switch and the key start
i02480863
B. Disconnect the solenoid with the active diagnostic
Transmission, SPN 738 - FMI 5 trouble code from the machine harness.
SMCS Code: 3139-038-T3 C. At the machine harness connector for the

Conditions Which Generate This Code: 900-PU) to contact 2 (wire 921-WH).
Expected Result:

Results:

Illustration 60
g01239004
Schematic of the transmission shift solenoid 5 solenoid has failed.
This diagnostic trouble code is associated with the Repair: The solenoid has failed. Replace the
transmission solenoid valve 5. The FMI 5 means that solenoid. Verify that the new solenoid corrects the
the ECU has determined that an open in the circuit problem.
exists.
STOP.
are listed below: Test Step 2. CHECK THE HARNESS FOR
AN OPEN.
• The return circuit of the solenoid is open. switch to the OFF position.
• The solenoid has failed. B. Disconnect the machine harness connector(s)

from the ECU.
C. The jumper wire that was installed in the previous
KENR5099-06 99
D. At the machine harness connector, measure It is unlikely that the ECU has failed. Exit this
the resistance from signal contact J1-58 (wire procedure and perform this procedure again. If
900-PU) to contact J1-60 (wire 921-WH). the cause of the diagnostic trouble code is not
Expected Result: ECM, always contact your dealership for possible
The resistance is less than 5.0 ohms. may greatly reduce repair time. See Testing and
Results:
STOP.
machine harness is correct. Proceed to Test Step • NO – The SPN 738 FMI 5 is not active. The
3. diagnostic trouble code does not exist at this time.
• NOT OK – The resistance is greater than 5000 caused by a poor electrical connection at one of
ohms. The resistance measurement is not correct. the harness connectors that was disconnected and
There is an open circuit in the machine harness. reconnected. Resume normal vehicle operation.
STOP.
machine harness.
i02480871
STOP. Transmission, SPN 738 - FMI 6

Test Step 3. CHECK IF THE DIAGNOSTIC SMCS Code: 3139-038-T3


fastened.

g01239004
Illustration 61
E. Operate the vehicle. Schematic of the transmission shift solenoid 5
F. Check the status of the SPN 738 FMI 5. This diagnostic trouble code is associated with the
Expected Result: that the ECU has determined that there is a short to
Results: are listed:
• YES – The SPN 738 FMI 5 is active. The • The energize circuit of the solenoid is shorted to
diagnostic trouble code has not been corrected. ground.
Repair: Check the circuit again. If the Caterpillar • The solenoid has failed.
ET service tool in order to perform a “Wiggle Test” • The ECU has failed. This is unlikely.
100 KENR5099-06

created diagnostic trouble codes and clear these Each resistance measurement is greater than 5000
diagnostic trouble codes when the original diagnostic ohms.
diagnostic trouble code of SPN 738 FMI 6 is Results:
Note: Use a digital multimeter for the measurements than 5000 ohms. The machine harness is correct.
System Response: • NOT OK – Each resistance measurement is not

All gears that are engaged by the solenoid are machine harness. The short is between J1-58 (wire
unavailable. The lockup clutch is turned OFF. 900-PU) and the circuit with the low resistance
measurement.
STOP.
C. Disconnect the solenoid with the active diagnostic TROUBLE CODE REMAINS.
The FMI 6 changes to FMI 5 when the solenoid is by excessive heat, battery acid, or chafing.
disconnected.
Results: wires that are associated with the circuit.
• YES – The FMI 6 changes to FMI 5 when the C. Reconnect all harness connectors. Make sure
solenoid is disconnected. The circuit is correct. that the harness connectors are fully seated and
Repair: The solenoid has failed. Replace the fastened.
problem. D. Turn the disconnect switch and the key start
STOP.
to Test Step 2. F. Check the status of the SPN 738 FMI 6.
Test Step 2. CHECK THE ENERGIZE Expected Result:

SHORT TO GROUND. The SPN 738 FMI 6 is active.
A. Turn the key start switch and the disconnect Results:

B. The solenoid remains disconnected from the diagnostic trouble code has not been corrected.
machine harness.
C. Disconnect the machine harness connector(s) Electronic Technician (ET) is available, use the Cat
from the ECU. ET service tool in order to perform a “Wiggle Test”
D. At the machine harness connector, measure the can detect shorts and opens in the machine wiring
resistance from the signal contact J1-58 (wire harness that are momentary or intermittent.
900-PU) to all contacts that are used in the
KENR5099-06 101

The initial diagnostic trouble code was probably Only gears that are engaged by the solenoid are
caused by a poor electrical connection or a available. The lockup clutch is turned OFF.
disconnected and reconnected. Resume normal Test Step 1. CHECK THE ENERGIZE
vehicle operation. STOP. CIRCUIT OF THE SOLENOID FOR A
i02680488
Transmission, SPN 739 - FMI 3 switch to the OFF position.
SMCS Code: 3139-038-T3 B. Disconnect the machine harness connectors from

901-WH) to all contacts that are used in the
Expected Result:

ohms.
Results:

g01346412
Illustration 62
Schematic of the transmission shift solenoid 6 • NOT OK – Each resistance measurement is not
This diagnostic trouble code is associated with the machine harness. The short is between J1-48
transmission solenoid valve 6. The FMI 3 means (901-WH) and the circuit that has a low resistance
that the ECU has determined that the voltage of the measurement.
The possible causes of the diagnostic trouble code machine harness.
are listed:
STOP.
• The energize circuit of the solenoid is shorted to TROUBLE CODE IS STILL ACTIVE.
• The ECU has failed. This is unlikely. contacts of the harness connectors and check the

102 KENR5099-06
C. Reconnect all harness connectors in order to i02680489

Also, make sure that the clips for each connector Transmission, SPN 739 - FMI 5
switch to the ON position. Conditions Which Generate This Code:
Expected Result:
Results:

Repair: Check the circuit again. It is unlikely g01346412

Illustration 63
perform this procedure again. If the cause of the Schematic of the transmission shift solenoid 6
ECU. Prior to replacing an ECU, always contact This diagnostic trouble code is associated with the
your dealership for possible consultation with transmission solenoid valve 6. The FMI 5 means that
Caterpillar. This consultation may greatly reduce the ECU has determined that an open in the circuit
repair time. See Testing and Adjusting, “Electronic exists.
STOP. are listed below:
• NO – The SPN 739 FMI 3 is not active. The • The energize circuit of the solenoid is open.
The initial diagnostic trouble code was probably • The return circuit of the solenoid is open.
short at one of the harness connectors that was • The solenoid has failed.
machine operation. STOP. • The ECU has failed. This is unlikely.

in this procedure.
System Response:


KENR5099-06 103
B. Disconnect the solenoid with the active diagnostic Repair: Repair the machine harness or replace the
trouble code from the machine harness. machine harness.
C. At the machine harness connector for the STOP.

901-WH) to contact 2 (wire 922-BR). Test Step 3. CHECK IF THE DIAGNOSTIC
The diagnostic trouble code is active. Then, the by excessive heat, battery acid, or chafing.
after the jumper wire is installed. B. Perform a 45 N (10 lb) pull test on each of the
Results:
• YES – The diagnostic trouble code remains active. that the harness connectors are fully seated and
The jumper wire does not affect the diagnostic that the clips for each connector are completely
trouble code. Proceed to Test Step 2. fastened.
• NO – The diagnostic is no longer active. The D. Turn the disconnect switch and the key start
solenoid has failed. switch to the ON position.
Repair: The solenoid has failed. Replace the E. Operate the vehicle.
problem. F. Check the status of the SPN 739 FMI 5.
STOP. Expected Result:
Test Step 2. CHECK THE HARNESS FOR The SPN 739 FMI 5 is active.
AN OPEN.
Results:
from the ECU. Repair: Check the circuit again. If the Caterpillar
C. The jumper wire that was installed in the previous ET service tool in order to perform a “Wiggle Test”
Test Step remains in place. on the machine wiring harness. The “Wiggle Test”
D. At the machine harness connector, measure harness that are momentary or intermittent.
the resistance from signal contact J1-48 (wire
901-WH) to contact J1-50 (wire 922-BR). It is unlikely that the ECU has failed. Exit this
Expected Result: the cause of the diagnostic trouble code is not
The resistance is less than 5.0 ohms. ECM, always contact your dealership for possible
Results: may greatly reduce repair time. See Testing and
machine harness is correct. Proceed to Test Step STOP.
3.
• NOT OK – The resistance is greater than 5000 diagnostic trouble code does not exist at this time.
104 KENR5099-06
Repair: The initial diagnostic trouble code was Test Step 1. CHECK THE SOLENOID.
probably caused by a poor electrical connection
at one of the harness connectors that was A. Turn the disconnect switch and the key start
disconnected and reconnected. Resume normal switch to the ON position. Do not start the engine.
vehicle operation.
STOP.
i02680491
Transmission, SPN 739 - FMI 6 Expected Result:
SMCS Code: 3139-038-T3 The FMI 6 changes to FMI 5 after the solenoid is
disconnected.
Results:


problem.
STOP.

to Test Step 2.

Illustration 64
g01346412 CIRCUIT OF THE SOLENOID FOR A
Schematic of the transmission shift solenoid 6 SHORT TO GROUND.
This diagnostic trouble code is associated with the A. Turn the key start switch and the disconnect
transmission solenoid valve 6. The FMI 6 means switch to the OFF position.
that the ECU has determined that there is a short to
ground in the solenoid circuit. B. The solenoid remains disconnected from the
machine harness.
are listed: C. Disconnect the machine harness connector(s)
from the ECU.
ground. D. At the machine harness connector, measure the
• The solenoid has failed. 901-WH) to all contacts that are used in the
Expected Result:
other diagnostic trouble codes. Ignore these Each resistance measurement is greater than 5000
created diagnostic trouble codes and clear these ohms.
trouble code has been corrected. Ensure that the Results:
active before performing this procedure. • OK – Each resistance measurement is greater
Note: Use a digital multimeter for the measurements Proceed to Test Step 3.
in this procedure.
System Response: greater than 5000 ohms. There is a short in the
machine harness. The short is between J1-48 (wire
All gears that are engaged by the solenoid are 901-WH) and the circuit with the low resistance
unavailable. The lockup clutch is turned OFF. measurement.
KENR5099-06 105
Repair: Repair the machine harness or replace the i02520930

machine harness.
STOP.
SMCS Code: 5479-038-L7
TROUBLE CODE REMAINS. Conditions Which Generate This Code:



fastened.
D. Turn the disconnect switch and the key start g01238970

Illustration 65
Schematic of the transmission lockup clutch solenoid
F. Check the status of the SPN 739 FMI 6. transmission lockup clutch solenoid. The FMI 3
means that the ECU has determined that the voltage
Expected Result: of the solenoid circuit is above normal.
The SPN 739 FMI 6 is active. The possible causes of the diagnostic trouble code
are listed:
Results:
diagnostic trouble code has not been corrected. • The energize circuit of the solenoid is shorted to
Electronic Technician (ET) is available, use the Cat • The ECU has failed. This is unlikely.
on the machine wiring harness. The “Wiggle Test” Note: The following test procedure may create
can detect shorts and opens in the machine wiring other diagnostic trouble codes. Ignore these
harness that are momentary or intermittent. created diagnostic trouble codes and clear these
It is unlikely that the ECU has failed. Exit this trouble code has been corrected. Ensure that the
procedure and perform this procedure again. If diagnostic trouble code of SPN 740 FMI 3 is
the cause of the diagnostic trouble code is not active before performing this procedure.
ECM, always contact your dealership for possible Note: Use a digital multimeter for the measurements
consultation with Caterpillar. This consultation in this procedure.
Adjusting, “Electronic Control Unit - Replace”. System Response:
STOP. The solenoid is engaged in a direct drive state.
short at one of the harness connectors that was A. Turn the key start switch and the disconnect
disconnected and reconnected. Resume normal switch to the OFF position.
vehicle operation. STOP.
106 KENR5099-06
B. Disconnect the machine harness connectors from Repair: Check the circuit again. It is unlikely
the solenoid and the ECU. that the ECU has failed. Exit this procedure and
C. At the machine harness connector for the ECU, diagnostic trouble code is not found, replace the
measure the resistance from contact J1-62 (wire ECU. Prior to replacing an ECU, always contact
705-PK) to all contacts that are used in the your dealership for possible consultation with
machine harness connectors for the ECU. Caterpillar. This consultation may greatly reduce
Expected Result: Control Unit - Replace”.
Each resistance measurement is greater than 5000 STOP.

ohms.
Results: diagnostic trouble code does not exist at this time.
• OK – Each resistance measurement is greater caused by a poor electrical connection or a
than 5000 ohms. The machine harness is correct. short at one of the harness connectors that was
Proceed to Test Step 2. disconnected and reconnected. Resume normal
i02480824
(705-PK) and the circuit that has a low resistance
measurement.
SMCS Code: 5479-038-L7
machine harness. Conditions Which Generate This Code:
STOP.



make sure that the connectors are fully seated. g01238970
Illustration 66
Also, make sure that the clips for each connector Schematic of the transmission lockup clutch solenoid
D. Turn the disconnect switch and the key start transmission lockup clutch solenoid. The FMI 5
switch to the ON position. means that the ECU has determined that an open
in the circuit exists.
F. Determine if the SPN 740 FMI 3 is active. are listed below:
Expected Result: • The energize circuit of the solenoid is open.
The SPN 740 FMI 3 is active. • The return circuit of the solenoid is open.
KENR5099-06 107
Note: The following test procedure may create D. At the machine harness connector, measure the
other diagnostic trouble codes. Ignore these resistance from signal contact J1-62 (wire 705-PK)
created diagnostic trouble codes and clear these to contact J1-60 (wire 921-WH).
trouble code has been corrected. Ensure that the Expected Result:
active before performing this procedure. The resistance is less than 5.0 ohms.

in this procedure.
System Response: machine harness is correct. Proceed to Test Step
3.
The solenoid will not engage.
• NOT OK – The resistance is greater than 5000
Test Step 1. CHECK THE SOLENOID. ohms. The resistance measurement is not correct.
switch to the ON position. Do not start the engine. Repair: Repair the machine harness or replace the
machine harness.
trouble code from the machine harness. STOP.
C. At the machine harness connector for the Test Step 3. CHECK IF THE DIAGNOSTIC
solenoid, place a jumper wire from contact 1 (wire TROUBLE CODE REMAINS.
705-PK) to contact 2 (wire 921-WH).
D. Observe the status of the SPN 740 FMI 5. contacts of the harness connectors and check the
The diagnostic trouble code is active. Then, the B. Perform a 45 N (10 lb) pull test on each of the
diagnostic trouble code changes from FMI 5 to FMI 6 wires that are associated with the circuit.
Results: make sure that the connectors are fully seated.
• YES – The diagnostic trouble code remains active. are completely fastened.
trouble code. Proceed to Test Step 2. D. Turn the disconnect switch and the key start
• NO – The diagnostic trouble code is no longer
active. The solenoid has failed. E. Operate the vehicle.
Repair: The solenoid has failed. Replace the F. Check the status of the SPN 740 FMI 5.
problem. Expected Result:
STOP. The SPN 740 FMI 5 is active.
Test Step 2. CHECK THE HARNESS FOR Results:

AN OPEN.
A. Turn the key start switch and the disconnect diagnostic trouble code has not been corrected.
B. Disconnect the machine harness connector(s) Electronic Technician (ET) is available, use the Cat
from the ECU. ET service tool in order to perform a “Wiggle Test”
C. The jumper wire that was installed in the previous can detect shorts and opens in the machine wiring
Test Step remains in place. harness that are momentary or intermittent.
108 KENR5099-06

The initial diagnostic trouble code was probably The solenoid will not engage.
i02480826
Transmission, SPN 740 - FMI 6 C. Disconnect the solenoid with the active diagnostic
SMCS Code: 5479-038-L7 trouble code from the machine harness.
Conditions Which Generate This Code: Expected Result:

disconnected.
Results:


problem.
STOP.
Illustration 67
g01238970
Schematic of the transmission lockup clutch solenoid to Test Step 2.
This diagnostic trouble code is associated with the Test Step 2. CHECK THE ENERGIZE
transmission lockup clutch solenoid. The FMI “6” CIRCUIT OF THE SOLENOID FOR A
means that the ECU has determined that there is a SHORT TO GROUND.
short to ground in the solenoid circuit.
The possible causes of this diagnostic trouble code switch to the OFF position.
are listed:
• The energize circuit of the solenoid is shorted to machine harness.
ground.
• The solenoid has failed. from the ECU.
• The ECU has failed. This is unlikely. D. At the machine harness connector, measure the
705-PK) to all contacts that are used in the
KENR5099-06 109
Each resistance measurement is greater than 5000 the cause of the diagnostic trouble code is not
ohms. found, replace the ECU. Prior to replacing an
Results: consultation with Caterpillar. This consultation
• OK – Each resistance measurement is greater Adjusting, “Electronic Control Unit - Replace”.
• NOT OK – Each resistance measurement is not • NO – The SPN 740 FMI 6 is not active. The
greater than 5000 ohms. There is a short in the diagnostic trouble code does not exist at this time.
machine harness. The short is between J1-62 (wire The initial diagnostic trouble code was probably
705-PK) and the circuit with the low resistance caused by a poor electrical connection or a
measurement. short at one of the harness connectors that was
Repair: Repair the machine harness or replace the machine operation. STOP.
machine harness.
i02733275
STOP.

TROUBLE CODE REMAINS. SMCS Code: 5479-038-WR
A. Inspect the harness connectors. Clean the Conditions Which Generate This Code:



E. Operate the vehicle. g01371111

Illustration 68
Schematic of the retarder solenoid on the CX31
Expected Result:
Results:


g01371109
can detect shorts and opens in the machine wiring Illustration 69
harness that are momentary or intermittent. Schematic of the retarder solenoid on the CX35
110 KENR5099-06
This diagnostic trouble code is associated with the Test Step 2. CHECK THE OPERATION OF
retarder solenoid. The FMI 3 means that the ECU THE ECU.
has determined that the voltage of the solenoid circuit
is above normal. The disconnect switch and the key start switch
remain in the OFF position. The machine harness
The possible causes of the diagnostic trouble code connectors for the solenoid and the ECU remain
are listed: disconnected.
• The solenoid has failed. A. At the J1 connector for the ECU, use a wire
removal tool to remove wire K744-BU from contact
• The energize circuit of the solenoid is shorted to J1-65.
B. Reconnect the machine harness J1 and J2
• The ECU has failed. This is unlikely. connectors to the ECU.
Note: The following test procedure may create C. Turn the disconnect switch and the key start
other diagnostic trouble codes. Ignore these switch to the ON position.
diagnostic trouble codes when the original diagnostic D. Observe the status of the active diagnostic code.
diagnostic trouble code of SPN 744 FMI 3 is Expected Result:
The FMI 3 changes to an FMI 5 after the wire is
Note: Use a digital multimeter for the measurements disconnected.
in this procedure.
Results:
CIRCUIT OF THE SOLENOID FOR A • YES – The FMI 3 changes to a FMI 5 after the wire
SHORT TO THE +BATTERY CIRCUIT. is disconnected. The ECU has responded correctly
to the condition of an open circuit. Reinstall the
A. Turn the key start switch and the disconnect disconnected wire to the correct space in the ECU
switch to the OFF position. before proceeding to the next Test Step. Proceed
to Test Step 3.
the solenoid and the ECU. • NO – The FMI 3 remains active. The status of the
active diagnostic code did not change when the
C. At the machine harness connector for the ECU, wire was disconnected from the ECU.
measure the resistance from contact J1-65 to all
contacts that are used in the machine harness Repair: The ECU has not responded correctly
connectors for the ECU. to the condition of an open circuit. The operation
of the ECU is not correct. Prior to replacing an
Expected Result: ECU, always contact your dealership for possible
Each resistance measurement is greater than 5000 may greatly reduce repair time. If the ECU
ohms. requires replacing, refer to Testing and Adjusting,
“Electronic Control Module (ECU) - Replace”.
Results:
STOP.
than 5000 ohms. The machine harness is correct. Test Step 3. CHECK IF THE DIAGNOSTIC
Proceed to Test Step 2. CODE IS STILL ACTIVE.
• NOT OK – Each resistance measurement is not A. Inspect the harness connectors. Clean the
greater than 5000 ohms. There is a short in the contacts of the harness connectors and check the
machine harness. The short is between J1-65 and wires for damage to the insulation that is caused
the circuit that has a low resistance measurement. by excessive heat, battery acid, or chafing.
Repair: Repair the machine harness or replace the B. Perform a 45 N (10 lb) pull test on each of the
machine harness. wires that are associated with the circuit.
STOP.
KENR5099-06 111
C. Reconnect all harness connectors in order to i02733276

Also, make sure that the clips for each connector Transmission, SPN 744 - FMI 5
SMCS Code: 5479-038-WR
switch to the ON position. Conditions Which Generate This Code:
F. Determine if the diagnostic code is active.
Expected Result:
The diagnostic code is active.
Results:
• YES – The diagnostic code is active. The

diagnostic code has not been corrected.
Repair: Check the circuit again. It is unlikely g01371111

Illustration 70
perform this procedure again. Prior to replacing an Schematic of the retarder solenoid on the CX31
ECU, always contact your dealership for possible
may greatly reduce repair time. If the ECU
requires replacing, refer to Testing and Adjusting,
STOP.
• NO – The diagnostic code is not active. The

diagnostic code does not exist at this time. The
initial diagnostic code was probably caused by a
poor electrical connection or a short at one of the
harness connectors that was disconnected and
reconnected. Resume normal machine operation.
STOP. Illustration 71
g01371109

retarder solenoid. The FMI 5 means that the ECU
has determined that an open in the circuit exists.

are listed below:

112 KENR5099-06

created diagnostic trouble codes and clear these The diagnostic code is active. Then, the diagnostic
diagnostic trouble codes when the original diagnostic code changes from FMI 5 to FMI 6 as the jumper
trouble code has been corrected. Ensure that the wire is installed.
active before performing this procedure. Results:
Note: Use a digital multimeter for the measurements • YES – The diagnostic code remains active. The
in this procedure. jumper wire does not affect the diagnostic code.
Test Step 1. CHECK THE SOLENOID FOR
A CX31. • NO – The diagnostic is no longer active. The
switch to the ON position. Do not start the engine. Repair: The solenoid has failed. Replace the
B. Disconnect the solenoid with the active diagnostic problem.
code from the machine harness.
STOP.
solenoid, place a jumper wire from contact 1 (wire Test Step 3. CHECK THE HARNESS FOR
K744-BU) to contact 2 (wire 921-WH). AN OPEN FOR A CX31.
D. Observe the status of the diagnostic code. A. Turn the key start switch and the disconnect
Expected Result:
The diagnostic code is active. Then, the diagnostic from the ECU.
code changes from FMI 5 to FMI 6 as the jumper
wire is installed. C. The jumper wire that was installed in the previous
Results:
D. At the machine harness connector, measure the
• YES – The diagnostic code remains active. The resistance from signal contact J1-65 to contact
jumper wire does not affect the diagnostic code. J1-60.
Expected Result:
solenoid has failed. The resistance is less than 5.0 ohms.
Repair: The solenoid has failed. Replace the Results:

problem. • OK – The resistance is less than 5.0 ohms. The
STOP. 5.
Test Step 2. CHECK THE SOLENOID FOR • NOT OK – The resistance is greater than 5000
A CX35. ohms. The resistance measurement is not correct.
switch to the ON position. Do not start the engine. Repair: Repair the machine harness or replace the
machine harness.
code from the machine harness. STOP.
C. At the machine harness connector for the Test Step 4. CHECK THE HARNESS FOR
solenoid, place a jumper wire from contact 1 (wire AN OPEN FOR A CX35.
K744-BU) to contact 2 (wire 923-GY).
D. Observe the status of the diagnostic code. switch to the OFF position.
KENR5099-06 113
B. Disconnect the harness connector(s) from the Results:

ECU.
• YES – The FMI 5 changes to a FMI 6 when the
C. The jumper wire that was installed in the previous pin is grounded at contact J2-4. The ECU has
Test Step remains in place. responded correctly to the condition of a grounded
circuit. The operation of the ECU is correct.
D. At the machine harness connector, measure the Reinstall the disconnected wire into the correct
resistance from signal contact J1-65 to contact spot in the ECU before proceeding to the next Test
J1-55. Step.
Expected Result: Proceed to Test Step 6.
The resistance is less than 5.0 ohms. • NO – The FMI 5 remains active. The status of
the active diagnostic code does not change when
Results: contact J1-65 is grounded.
• OK – The resistance is less than 5.0 ohms. The Repair: The ECU has not responded correctly to
machine harness is correct. Proceed to Test Step the condition of a grounded circuit. The operation
5. of the ECU is not correct.
• NOT OK – The resistance is greater than 5000 Prior to replacing an ECU, always contact your
ohms. The resistance measurement is not correct. dealership for possible consultation with Caterpillar.
There is an open circuit in the machine harness. This consultation may greatly reduce repair time.
If the ECU requires replacing, refer to Testing
Repair: Repair the machine harness or replace the and Adjusting, “Electronic Control Module (ECU)
machine harness. - Replace”.
STOP. STOP.
Test Step 5. CHECK THE OPERATION OF Test Step 6. CHECK IF THE DIAGNOSTIC
THE ECU. CODE REMAINS.
The disconnect switch and the key start switch A. Inspect the harness connectors. Clean the
remain in the OFF position. The harness connector contacts of the harness connectors and check the
for the solenoid and the connectors for the ECU wires for damage to the insulation that is caused
remain disconnected. by excessive heat, battery acid, or chafing.
A. Remove the jumper wire that was installed in the B. Perform a 45 N (10 lb) pull test on each of the
last test step. wires that are associated with the circuit.
B. At the J2 connector for the ECU, use a wire C. Reconnect all harness connectors. Make sure
removal tool to remove wire K744-BU from contact that the harness connectors are fully seated and
J1-65. that the clips for each connector are completely
fastened.
C. Reconnect the machine harness connectors to
the ECU. D. Turn the disconnect switch and the key start
switch to the ON position. E. Operate the vehicle.
E. Use a multimeter probe that is not connected to F. Check the status of the diagnostic code.
a multimeter or a similar device to make contact
with the ECU at contact J1-65 through the empty Expected Result:
space in the J1 connector.
The diagnostic code is active.
F. Observe the status of the diagnostic code. Ground
the other end of the multimeter probe to frame Results:
ground.
• YES – The diagnostic code is active. The
Expected Result: diagnostic code has not been corrected.
The FMI 5 changes to a FMI 6 when the pin is

grounded at contact J1-65.
114 KENR5099-06
Repair: Check the circuit again. It is unlikely This diagnostic trouble code is associated with the
that the ECU has failed. Exit this procedure and retarder solenoid. The FMI 6 means that the ECU
perform this procedure again. Prior to replacing an has determined that there is a short to ground in the
ECU, always contact your dealership for possible solenoid circuit.
may greatly reduce repair time. If the ECU The possible causes of this diagnostic trouble code
requires replacing, refer to Testing and Adjusting, are listed:
STOP. ground.
• NO – The diagnostic code is not active. The • The solenoid has failed.
diagnostic code does not exist at this time. The
initial diagnostic code was probably caused • The ECU has failed. This is unlikely.
by a poor electrical connection at one of the
harness connectors that was disconnected and Note: The following test procedure may create
reconnected. Resume normal vehicle operation. other diagnostic trouble codes. Ignore these
STOP. created diagnostic trouble codes and clear these
i02733278
Transmission, SPN 744 - FMI 6 active before performing this procedure.
SMCS Code: 5479-038-WR Note: Use a digital multimeter for the measurements
in this procedure.

Expected Result:

disconnected.
g01371111 Results:
Illustration 72

problem.
STOP.

to Test Step 2.

SHORT TO GROUND.
g01371109
Illustration 73
Schematic of the retarder solenoid on the CX35 A. Turn the key start switch and the disconnect
KENR5099-06 115
B. The solenoid remains disconnected from the Results:

machine harness.
C. Disconnect the machine harness connector(s) diagnostic trouble code has not been corrected.
from the ECU.
D. At the machine harness connector, measure the Electronic Technician (Cat ET) is available, use the
resistance from the signal contact J1-65 (wire Cat ET service tool in order to perform a “Wiggle
K744-BU) to all contacts that are used in the Test” on the machine wiring harness. The “Wiggle
machine harness connectors for the ECU. Test” can detect shorts and opens in the machine
wiring harness that are momentary or intermittent.
Expected Result:
Each resistance measurement is greater than 5000 procedure and perform this procedure again. If
ohms. the cause of the diagnostic trouble code is not
Results: ECM, always contact your dealership for possible
• OK – Each resistance measurement is greater may greatly reduce repair time. See Testing and
than 5000 ohms. The machine harness is correct. Adjusting, “Electronic Control Unit - Replace”.
STOP.
greater than 5000 ohms. There is a short in the • NO – The SPN 744 FMI 6 is not active. The
machine harness. The short is between J1-65 (wire diagnostic trouble code does not exist at this time.
K744-BU) and the circuit with the low resistance The initial diagnostic trouble code was probably
measurement. caused by a poor electrical connection at one of
Repair: Repair the machine harness or replace the reconnected. Resume normal machine operation.
machine harness. STOP.
STOP.
i02869340
Test Step 3. CHECK IF THE DIAGNOSTIC Transmission, SPN 973 - FMI 9

SMCS Code: 1129-038
contacts of the harness connectors and check the Conditions Which Generate This Code:


fastened.


g01350167
Illustration 74
This diagnostic code is associated with the selector
Expected Result: for the engine retarder. The illustration for the J1939
Data Link may not represent all of the connections
The SPN 744 FMI 6 is active. for the components that are on machines that are
covered by this manual. Refer to the electrical system
schematic for your machine in order to verify the
J1939 Data Link connections.
116 KENR5099-06
Note: This diagnostic code is recorded when the H. Check the connectors for dirty contacts or
Transmission ECU does not receive expected corroded contacts.
information from the selector for the engine retarder
for a period of more than five seconds. I. Check each pin and each socket of the machine
Test Step 1. VERIFY THE HARDWARE are properly installed. The contacts should mate
AND THE SOFTWARE PART NUMBERS. correctly when the two pieces of the connector
A. Verify that the following information is correct:
Expected Result:
• The part number of the flash software for the
Transmission ECU The machine harness connectors are tight and free
of corrosion.
• The part number of the Transmission ECU
Results:
Note: Consult the Business Unit that produces the
product for the correct part numbers of the flash • OK – The machine harness connectors are tight
software. and free of corrosion. Proceed to Test Step 3.
Expected Result: • NOT OK – The machine harness connectors are

in need of repair.
All the part numbers are correct.
Results: machine harness.
• OK – All of the part numbers are correct. Proceed STOP.

to Test Step 2.
Test Step 3. CHECK FOR SHORTS TO
• NOT OK – All of the part numbers are not correct. GROUND
Repair: The ECU has the wrong part number or A. The disconnect switch remains in the OFF
the incorrect software is installed. Replace the ECU position.
with a module that has the correct part number.
Flash the correct software. See the Testing and B. Disconnect the machine harness from all
Adjusting, “Electronic Control Unit - Flash Program” electronic control modules that use the J1939
section of this manual. Data Link.
STOP. C. At the machine harness for the Transmission

ECU, measure the resistance between contacts
Test Step 2. INSPECT THE HARNESS J2-67 and J2-68 of the J1939 Data Link and frame
CONNECTIONS. ground.
A. Turn the disconnect switch to the OFF position. Expected Result:
B. Inspect all harness connections that are related The resistance is greater than 5000 Ohms.
to the J1939 Data Link. Make sure that the
connectors are clean and tight. Results:
C. Check the connectors for proper mating. Ensure • OK – The resistance is greater than 5000 Ohms.
that all the seals are present and in place. The harness circuit resistance is correct. Proceed
to Test Step 4.
abrasion. • NOT OK – The resistance is less than 5000 Ohms.
The machine harness has failed.
E. Check the wires at the connector. Ensure that the
wires are secured tightly into the connector. Take Repair: There is a short between frame ground
care not to pull the wire out of the connector. and the J1939 Data Link circuit in the machine
harness. Repair the machine harness or replace
F. Check the exposed wires at the connectors for the machine harness. See the Testing and
nicks or signs of abrasion. Adjusting, “Wiring Harness (Short Circuit) - Test”
section of this manual.
STOP.
KENR5099-06 117
Test Step 4. CHECK THE MACHINE Expected Result:

HARNESS FOR A SHORT TO THE
+BATTERY CIRCUIT. The SPN 973 FMI 9 is active.
A. The disconnect switch remains in the OFF Results:

position.
B. All related electronic control modules remain diagnostic trouble code has not been corrected.
disconnected from the machine harness.
C. At the machine harness connector for the that the ECU has failed. Exit this procedure and
Transmission ECU, perform the checks that are perform this procedure again. If the cause of the
listed here: diagnostic trouble code is not found, replace the
• Measure the resistance between the connector your dealership for possible consultation with
contact J2-67 and all sources of +battery. Caterpillar. This consultation may greatly reduce
• Measure the resistance between connector Control Unit - Replace”.
STOP.
Expected Result:
The resistance is greater than 5000 Ohms. diagnostic trouble code does not exist at this time.
Results: caused by a poor electrical connection at one of
• OK – The harness circuit resistance is correct. reconnected. Resume normal vehicle operation.
• NOT OK – The resistance is less than 5000 Ohms. i02869584

Repair: There is a short between the +battery

circuit and the circuits of the J1939 Data Link 19
circuit in the machine harness. Repair the machine
harness or replace the machine harness. See the SMCS Code: 1129-038
Testing and Adjusting, “Wiring Harness (Short
Circuit) - Test” section of this manual. Conditions Which Generate This Code:
STOP.


C. Reconnect all harness connectors. Make sure g01350167

Illustration 75
fastened. This diagnostic code is recorded when the data from
the selector for the engine retarder is not available on
D. Turn the disconnect switch and the key start the J1939 Data Link. The data link is not the cause of
switch to the ON position. this diagnostic trouble code.

118 KENR5099-06
Note: The illustration for the J1939 Data Link may not • NOT OK – The Engine control unit does not have
represent all of the connections for the components active diagnostic codes for the retarder.
that are on machines that are covered by this
manual. Refer to the electrical system schematic for Repair: Contact your dealership for possible
your machine in order to verify the J1939 Data Link consultation with Caterpillar. This consultation may
connections. greatly reduce repair time.
The possible causes of the diagnostic trouble code STOP.

are listed:
i03019306
• The feature is not configured in Cat ET.
• The component has an active diagnostic.
8
Test Step 1. VERIFY THE
CONFIGURATION OF THE FEATURE. SMCS Code: 3120-038
A. Verify that the following information is correct: Conditions Which Generate This Code:
• The parameter is set in Cat ET.

Expected Result:
All of the information is correct.
Results:
• OK – All of the information is correct. Proceed to

Test Step 2.

Repair: The parameters have not been configured g01527008
Illustration 76
correctly. See the Systems Operation Section,
“Programmable Parameters” section of this Schematic of the position sensor for the retarder
manual.
This diagnostic trouble code is associated with
STOP. the position sensor for the retarder. The FMI 8
means that the ECU has determined that the signal
Test Step 2. CHECK THE ENGINE frequency or the signal pulse width is not within the
CONTROL UNIT FOR ACTIVE expected range.
The position sensor is a PWM sensor that has a
A. Check the Engine control unit for active diagnostic frequency of 500 hertz. The duty cycle operates
trouble codes for the retarder. from a range of 10% to 90%. As the lever is moved
downward the duty cycle increases.
Expected Result:
The possible causes of this diagnostic code are listed
The Engine control unit has active diagnostic codes below:
for the retarder.
Results:
• Intermittent connections or poor connections
• OK – The Engine control unit has active diagnostic
codes. • Mechanical devices are loose.
Repair: Perform the procedures for the retarder. • The ECU has failed. This is unlikely.
Verify that clearing the diagnostic trouble codes on
the Engine control unit has corrected the problem.
STOP.
KENR5099-06 119
Note: The following test procedure may create E. Monitor the signal of the sensor with the digital
other diagnostic trouble codes. Ignore these multimeter.
diagnostic trouble codes when the original diagnostic F. Without disconnecting the sensor or the hardware
trouble code has been corrected. Ensure that the that is associated with the sensor from the
diagnostic trouble code of SPN 1716 FMI 8 is machine, take the sensor through the full
active before performing this procedure. operating range of the sensor.
Note: Use a digital multimeter for the measurements Note: On some machines, it may be necessary to
in this procedure. start the engine in order to take the sensor through
the full operating range of the sensor. Push the pedal
Test Step 1. CHECK FOR POWER AT THE in order to see a change.
SENSOR.
Expected Result:
A. Do not disconnect the harness connector from the
sensor. The sensor's signal responds in the manner that is
described at the begining of this procedure.
B. At the back of the harness connector for the
sensor, use an electrical spoon in order to insert Results:
a multimeter probe along the voltage supply wire
(contact A). • OK – The sensor's signal responds correctly. The
sensor is operating correctly. Proceed to Test Step
C. Turn the key start switch and the disconnect 3.
• NOT OK – The sensor's signal does not respond
D. Measure the voltage from contact A to frame correctly. The sensor is NOT operating correctly.
ground.
Expected Result:
STOP.
The voltage is 24 DCV.
Test Step 3. CHECK THE SIGNAL
Results: CIRCUIT AT THE ECU.
• OK – The voltage is 24 DCV. Proceed to Test Step A. Turn the key start switch and the disconnect
2. switch to the OFF position.
• NOT OK – The voltage is not 24 DCV. The circuit B. Use an electrical spoon in order to insert the
is open. multimeter probe into the back of the connector
for the ECU along J2-42 (wire Y924-OR).
machine harness. C. Connect the other multimeter probe to a clean
source of frame ground.
STOP.
Test Step 2. CHECK THE SIGNAL switch to the ON position.
CIRCUIT OF THE SENSOR.
E. Monitor the signal of the sensor with the digital
A. Turn the key start switch and the disconnect multimeter.
F. Without disconnecting the sensor or the hardware
B. At the back of the harness connector for the that is associated with the sensor from the
sensor, remove the multimeter probe from contact machine, take the sensor through the full
A and insert the probe with the electrical spoon operating range of the sensor.
along the signal wire (contact C).
Note: On some machines, it may be necessary to
C. At the back of the harness connector for the start the engine in order to take the sensor through
sensor, use an electrical spoon in order to insert the full operating range of the sensor. Push the pedal
the multimeter probe along the ground wire in order to see a change.
(contact B).

120 KENR5099-06
Expected Result: C. Reconnect all harness connectors. Make sure

The sensor's signal responds in the manner that is that the clips for each connector are completely
described at the begining of this procedure. fastened.

• OK – The sensor's signal responds correctly. The
sensor is operating correctly. Proceed to Test Step E. Operate the vehicle.
4.
• NOT OK – The sensor's signal does not respond
correctly. The harness has failed. Expected Result:
machine harness.
Results:
STOP.
Test Step 4. CHECK THE SIGNAL CIRCUIT diagnostic trouble code has not been corrected.
FOR A SHORT IN THE HARNESS.
A. The key start switch and the disconnect switch that the ECU has failed. Exit this procedure and
remain in the OFF position. perform this procedure again. Prior to replacing an
B. Disconnect the machine harness connectors from consultation with Caterpillar. This consultation
the sensor and the ECU. may greatly reduce repair time. See Testing and
C. Measure the resistance between contact J2-42
(wire Y924-OR) and all contacts that are used in STOP.
the machine harness connectors for the ECU.
The resistance is greater than 5000 ohms. caused by a poor electrical connection at one of
Results: reconnected. Resume normal vehicle operation.
STOP.
• OK – The resistance is greater than 5000 ohms.
The circuit is correct. Proceed to Test Step 5.
i02869685

The signal circuit is shorted to another circuit in
the harness. 13
Repair: Repair the machine harness or replace the SMCS Code: 3120-038
machine harness.
STOP.
This diagnostic trouble code is recorded when the
Test Step 5. CHECK IF THE DIAGNOSTIC ECU detects the signal of the sensor as being out of
TROUBLE CODE REMAINS calibration.
A. Inspect the harness connectors. Clean the Note: The ECU provides power to the sensor. The
contacts of the harness connectors and check the sensor does not connect directly to the frame ground.
wires for damage to the insulation that is caused The sensor connects to the return circuit of the ECU.
by excessive heat, battery acid, or chafing. The ECU internally connects the return wire to frame
ground. In order to correct this diagnostic trouble
B. Perform a 45 N (10 lb) pull test on each of the code, calibrate the sensor.
KENR5099-06 121
CALIBRATION • The sensor has failed.

A. Perform the calibration procedure for the sensor. • The ECU has failed. This is unlikely.
See the calibration procedure in the manual for
your vehicle for more information. Note: The following test procedure may create
Expected Result: created diagnostic trouble codes and clear these
The calibration procedure was performed trouble code has been corrected. Ensure that the
successfully. diagnostic trouble code of SPN 3027 FMI 3 is
Results:
• YES – The calibration procedure was performed in this procedure.
successfully. Resume normal machine operation.
STOP. Note: The ECU reads a voltage of 0.3 VDC if the
sensor loses the power connection to the 5 VDC. The
• NO – The calibration was not successful. ECU reads a voltage of 5.4 VDC if the sensor loses
the connection to ground. The output is 4.5 VDC
Repair: Repeat the calibration procedure for when the sensor is completely immersed in fluid.
the sensor. See the calibration procedure in the
manual for your vehicle for more information. Test Step 1. CHECK THE SENSOR.
STOP. A. Turn the disconnect switch and the key start
i02898172
B. Disconnect the sensor with the active diagnostic
Transmission, SPN 3027 - FMI trouble code from the machine harness.
3 C. At the machine harness connector for the sensor,

place a jumper wire from contact 2 (wire 202-BK)
SMCS Code: 1435-038-OC to contact 3 (wire 425-PK).
Conditions Which Generate This Code: D. Observe the status of the SPN 3027 FMI 3.
Expected Result:
The diagnostic trouble code changes from FMI 3 to

Results:


sensor has failed.
g01443191
Illustration 77
Schematic of the oil level sensor for the transmission
STOP.
This diagnostic trouble code is associated with the oil
level sensor for the transmission. The FMI 3 means Test Step 2. CHECK THE ENERGIZE
that the ECU has determined that the voltage of the CIRCUIT OF THE SENSOR FOR A SHORT
sensor is above 4.8 ± 0.04 VDC. TO THE +BATTERY CIRCUIT.
The possible causes of the diagnostic trouble code A. Turn the key start switch and the disconnect
are listed: switch to the OFF position.
• The energize circuit of the sensor is shorted to the B. Disconnect the machine harness connectors from
+battery circuit. the sensor and from the ECU.
122 KENR5099-06
C. At the machine harness connector for the ECU, Repair: Check the circuit again. It is unlikely
measure the resistance from contact J1-36 (wire that the ECU has failed. Exit this procedure and
709-OR) to all contacts that are used in the perform this procedure again. If the cause of the
machine harness connectors for the ECU. diagnostic trouble code is not found, replace the
Expected Result: your dealership for possible consultation with
Each resistance measurement is greater than 5000 repair time. See Testing and Adjusting, “Electronic
ohms. Control Unit - Replace”.
Results: STOP.
• OK – Each resistance measurement is greater • NO – The SPN 3027 FMI 3 is not active. The
than 5000 ohms. The machine harness is correct. problem does not exist at this time. The initial
Proceed to Test Step 3. diagnostic trouble code was probably caused by
a poor electrical connection or a short at one of
• NOT OK – Each resistance measurement is not the harness connectors that was disconnected and
greater than 5000 ohms. There is a short in the reconnected. Resume normal vehicle operation.
machine harness. The short is between J1-36 STOP.
(709-OR) and the circuit that has a low resistance
measurement.
i02898174

machine harness.
4
STOP.
SMCS Code: 1435-038-OC
TROUBLE CODE IS STILL ACTIVE. Conditions Which Generate This Code:



D. Turn the disconnect switch and the key start g01443191

Illustration 78
Schematic of the oil level sensor for the transmission
F. Determine if the SPN 3027 FMI 3 is active. transmission oil temperature sensor. The FMI 4
means that the ECU has determined that the voltage
Expected Result: of the circuit for the temperature sensor is below
normal.
Results: are listed below:
• YES – The SPN 3027 FMI 3 is active. The problem • The signal circuit for the sensor is shorted to
has not been corrected. ground.

KENR5099-06 123
Note: The following test procedure may create Test Step 3. CHECK THE SIGNAL CIRCUIT
other diagnostic trouble codes. Ignore these FOR A SHORT IN THE HARNESS.
diagnostic trouble codes when the original diagnostic A. The key start switch and the disconnect switch
trouble code has been corrected. Ensure that the remain in the OFF position.
active before performing this procedure. B. Disconnect the machine harness connectors from
the sensor and the ECU.
in this procedure. C. Measure the resistance between contact J1-36
(wire 425-PK) and all of the contacts that are used
Test Step 1. INSPECT THE SENSOR. in the machine harness connectors for the ECM.
A. Perform a visual inspection of the sensor, the Expected Result:

wiring for the sensor and the hardware that is
associated with the sensor. Each resistance measurement is greater than 5000
ohms.
Expected Result:
Results:
There is no apparent damage to the sensor, the wiring
for the sensor or the hardware that is associated with • OK – Each of the resistance measurements are
the sensor. greater than 5000 ohms. The circuit is correct.
Results:
• OK – There is no apparent damage to the sensor, The signal circuit is shorted to another circuit in
the wiring for the sensor or the hardware that is the harness.
associated with the sensor. Proceed to Test Step 2.
• NOT OK – There is apparent damage to the machine harness.
sensor, the wiring for the sensor or the hardware
that is associated with the sensor. STOP.
Repair: Replace the damaged part. Test Step 4. CHECK IF THE DIAGNOSTIC
Test Step 2. CHECK THE SENSOR. contacts of the harness connectors and check the
A. Disconnect the harness connector from the by excessive heat, battery acid, or chafing.
sensor.
B. Monitor the status of the diagnostic trouble code. wires that are associated with the circuit.

The diagnostic trouble code changes from a FMI 4 Also, make sure that the clips for each connector
to a FMI 3. are completely fastened.

• YES – The FMI 4 does not change to a FMI 3.
The harness and the ECU are correct. The sensor E. Operate the machine.
is faulty.
Expected Result:
STOP.
• NO – The diagnostic trouble code is no longer
active. A problem exists in the harness or the ECU.
It is unlikely that the ECU has failed. Proceed to
Test Step 3.
124 KENR5099-06
Results:
• YES – The SPN 3027 FMI 4 is active. The problem

has not been corrected.


STOP.

problem does not exist at this time. The initial
diagnostic trouble code was probably caused by
a poor electrical connection or a short at one of
reconnected. Resume normal machine operation.
STOP.
KENR5099-06 125
i02799423

2
SMCS Code: 1435-038; 3107-038; 3108-038
g01399075
Illustration 79
Schematic of the Driveline Power Take-Off (DPTO) when engaged
This diagnostic trouble code is associated with the Note: Use a digital multimeter for the measurements
driveline PTO switch. The FMI 2 recorded when the in this procedure.
ECU reads the signal from the switch and the ECU
determines that the signal is erratic, intermittent, or System Response:
incorrect.
The amber warning lamp is illuminated. The pump
The possible causes of this diagnostic trouble code may not engage correctly and the machine may be
are listed: allowed to move.
• The DPTO switch has failed in the closed position Test Step 1. VERIFY THE SOFTWARE
and the driveline is engaged. VERSION
• J2-54 is shorted to ground. Note: Check and record the latest software version
for the transmission electronic controls from SIS.
A. Verify that the latest version of software has been
Note: The following test procedure may create loaded to the ECU.
created diagnostic trouble codes and clear the Expected Result:
trouble code has been corrected. Ensure that the All of the software is current.
126 KENR5099-06
Results: C. Place the switch in the disengaged position.

Measure the resistance of the contacts with the
• OK – All of the software is current. Proceed to Test digital multimeter. Note the resistance.
Step 2.
D. Place the switch in the engaged position. Measure
• NOT OK – There is a more recent software the resistance of the contacts with the digital
release that is available. multimeter. Note the resistance.
Repair: Flash all controls with the latest software Expected Result:
release. Refer to Testing and Adjusting, “Electronic
Control Unit - Flash Program” for more information. The resistance is greater than 5000 ohms in the
disengaged position and the resistance is less than 5
STOP. ohms in the engaged position.
Test Step 2. CHECK THE HARNESS. Results:
A. Turn the key start switch to the OFF position. • OK – The resistance is greater than 5000 ohms in
the disengaged position and the resistance is less
B. Inspect the harness. than 5 ohms in the engaged position. The switch is
operating correctly. Proceed to Test Step 4.
C. Check for the proper mating.
• NOT OK – The resistance is less than 5 ohms
D. Check the exposed wires for nicks and abrasions. in the disengaged position and in the engaged
position. The switch has failed. Replace the switch.
E. Check for moisture, dirt, or corrosion. Ensure that the new switch has corrected the
problem. STOP.
F. Check the pin/socket for a proper fit.
G. Disconnect the machine harness connectors from TROUBLE CODE IS STILL ACTIVE.
the Transmission ECM.
H. Place the switch in the open or disengaged contacts of the harness connectors and check the
position. wires for damage to the insulation that is caused
I. At the machine harness connector, measure
the resistance from connector contact J2-54 to B. Perform a 45 N (10 lb) pull test on each of the
ground. wires that are associated with the circuit.

The resistance should be more than 5000 ohms. Also, make sure that the clips for each connector
Results:
• OK – The resistance is more than 5000 ohms. The switch to the ON position.
machine harness is correct. Proceed to test step 3.
There is an closed circuit in the machine harness. F. Determine if the diagnostic trouble code is active.
The closed circuit exists in the wire with the low
resistance. Expected Result:
Repair: Repair the machine harness or replace the The diagnostic trouble code is active.
machine harness.
Results:
STOP.
• YES – The diagnostic trouble code is active. The
Test Step 3. CHECK THE OPERATION OF problem has not been corrected.
THE SWITCH.
A. The key start switch remains in the OFF position.
B. Disconnect the switch from the machine harness.

KENR5099-06 127
Repair: Check the circuit again. It is unlikely • The ECU has failed. This is unlikely.
perform this procedure again. Prior to replacing an Note: The following test procedure may create
ECU, always contact your dealership for possible other diagnostic trouble codes. Ignore these
consultation with Caterpillar. This consultation may created diagnostic trouble codes and clear these
greatly reduce repair time. If the ECU requires diagnostic trouble codes when the original diagnostic
replacement, refer to Testing and adjusting, trouble code has been corrected. Ensure that the
“Electronic Control Unit - Replace”. diagnostic trouble code of SPN 3509 FMI 3 is
STOP.
• NO – The diagnostic trouble code is not active. in this procedure.
caused by a poor electrical connection or a Test Step 1. CHECK THE VOLTAGE AT
short at one of the harness connectors that was THE SENSOR
disconnected and reconnected. The problem does
not exist at this time. Resume normal machine A. Turn the disconnect switch and the key start
operation. STOP. switch to the ON position.
B. Disconnect the machine harness connector from

i02499568
the sensor.
Transmission, SPN 3509 - FMI C. At the machine harness connector for the sensor,
3 measure the voltage from connector contact
1 (wire 709-OR) to connector contact 2 (wire
SMCS Code: 1439-038; 7610-038-DTN 202-BK). Measure the voltage from connector
contact 1 (wire 709-OR) to frame ground.
Expected Result:
Both voltage measurements are 5.0 ± 0.5 DCV.
Results:
• OK – Both voltage measurements are 5.0 ± 0.5

DCV. The voltage is correct. Proceed to Test Step
3.
• NOT OK – The voltage measurement from

connector contact 1 (wire 709-OR) to the frame
ground is 5.0 ± 0.5 DCV. However, the voltage
measurement from connector contact 1 to
g01249620 connector contact 2 is not 5.0 ± 0.5 DCV. The
Illustration 80
return circuit is faulty in the machine harness.
Schematic of the 5 volt sensor supply
Repair: The return circuit is faulty in the machine
The 5 volt power supply provides power to the oil harness. Refer to the complete Electrical System
level sensor for the transmission. Schematic for the vehicle that is being serviced.
Examine all connection points in the return circuit
The SPN 3509 FMI 3 diagnostic trouble code is for the sensor. Ensure that all connections are
recorded when the ECU reads the voltage of the clean and secure. Make sure that the connections
sensor supply circuit as higher than the normal are in good condition. Repair the machine harness
voltage. or replace the machine harness.
The following is a list of possible causes for this STOP.

diagnostic trouble code:
• NOT OK – Both of the voltage measurements are
• The sensor supply circuit is shorted to the +battery greater than 5.0 ± 0.5 DCV. There may be a short
circuit. in the machine harness. Proceed to Test Step 2.
• The return circuit is open in the machine harness.

• A sensor has failed.
128 KENR5099-06
Test Step 2. CHECK THE HARNESS FOR F. Determine if the SPN 3509 FMI 3 diagnostic
A SHORT TO THE +BATTERY trouble code is active.
The machine harness connector remains Expected Result:

disconnected from the sensor.
The SPN 3509 FMI 3 diagnostic trouble code is
A. Turn the disconnect switch and the key start active.
Results:
B. Disconnect the machine harness connectors J1
and J2 from the ECU. • YES – The SPN 3509 FMI 3 diagnostic trouble
code is active. The problem has not been
C. At the harness connector J1, check the resistance corrected. The sensor may have failed or the ECU
from contact J1-11 (wire 709-OR) to all of the other may have failed.
+battery contacts that are connected to the ECU.
Repair: Replace the pressure sensor.
Expected Result:
Replace the pressure sensor. After the sensor
Each resistance measurement is greater than 5000 is replaced, perform this test again. It is unlikely
ohms. that the ECU has failed. Exit this procedure and
Results: diagnostic trouble code is not found, replace the
• OK – Each resistance measurement is greater your dealership for possible consultation with
than 5000 ohms. The supply circuit is not shorted Caterpillar. This consultation may greatly reduce
to a +battery circuit. Proceed to Test Step 3. repair time. See Testing and Adjusting, “Electronic
• NOT OK – One or more of the resistance
measurements is less than 5000 ohms. There is a STOP.
short in the machine harness.
• NO – The SPN 3509 FMI 3 diagnostic trouble
Repair: The power supply circuit is shorted to a code is not active. The problem does not exist at
+battery circuit in the machine harness. Refer to this time. The initial diagnostic trouble code was
the complete Electrical System Schematic for the probably caused by a poor electrical connection or
vehicle that is being serviced. Examine the supply a short at one of the harness connectors that was
circuit in order to determine the location of the disconnected and reconnected. Resume normal
problem. Repair the machine harness or replace vehicle operation. STOP.
the machine harness.
STOP.





KENR5099-06 129
i02499567 Results:
Transmission, SPN 3509 - FMI • OK – The diagnostic trouble code is not active.
4 The harness circuit is correct. The sensor that was
just disconnected has failed.
SMCS Code: 1439-038; 7610-038-DTN
STOP.
• NOT OK – The diagnostic trouble code is still

active. The machine harness may be shorted to
ground. Proceed to Test Step 2.
Test Step 2. CHECK FOR A SHORT TO

GROUND
B. Disconnect the machine harness from the ECU.
C. At the harness connector for the ECU, measure

g01249620
Illustration 81 the resistance between frame ground and contact
Schematic of the 5 volt sensor supply J1-11 (wire 709-OR) of the sensor supply circuit.
The 5 volt power supply provides power to the oil level Expected Result:
sensor for the transmission. The FMI 4 is recorded
when the ECU reads the voltage of the signal wire as The resistance is greater than 5000 ohms.
being below normal and/or shorted to ground.
Results:
The following is a list of possible causes for this
diagnostic trouble code: • OK – The resistance is greater than 5000 ohms.
The harness circuit resistance is correct. The ECU
• The sensor supply circuit is shorted to the ground. may have failed.
• A sensor has failed. Repair: Check the circuit again. If the Caterpillar
• The ECU has failed. This is unlikely. ET service tool in order to perform a “Wiggle Test”
Note: The following test procedure may create can detect shorts and opens in the machine wiring
other diagnostic trouble codes. Ignore these harness that are momentary or intermittent.
diagnostic trouble codes when the original diagnostic It is unlikely that the ECU has failed. Exit this
trouble code has been corrected. Ensure that the procedure and perform this procedure again. If
diagnostic trouble code of SPN 3509 FMI 4 is the cause of the diagnostic trouble code is not
active before performing this procedure. found, replace the ECU. Prior to replacing an
Note: Use a digital multimeter for the measurements consultation with Caterpillar. This consultation
in this procedure. may greatly reduce repair time. See Testing and
Test Step 1. CHECK THE SENSOR
STOP.
switch to the ON position. • NOT OK – The resistance is less than 5000 ohms.
Then, observe the status of the diagnostic trouble
code.
Expected Result:
The diagnostic trouble code is not active.

130 KENR5099-06
Repair: The 709-OR wire is shorted to ground Note: The following test procedure may create
in the machine harness. Refer to the complete other diagnostic trouble codes. Ignore these
Electrical System Schematic for your machine. created diagnostic trouble codes and clear these
Check all harness connectors that are in the power diagnostic trouble codes when the original diagnostic
supply circuit. Ensure that the connectors are trouble code has been corrected. Ensure that the
clean and secure. Repair the machine harness or diagnostic trouble code of SPN 3823 FMI 3 is
replace the machine harness. active before performing this procedure.
STOP. Note: Use a digital multimeter for the measurements

in this procedure.
i02492242
Test Step 1. CHECK THE VOLTAGE AT
Transmission, SPN 3823 - FMI THE SENSOR.
3 A. Turn the disconnect switch and the key start
SMCS Code: 1439-038-VC; 3101-038-NS
B. Disconnect the sensor from the machine harness.
measure the voltage between contact 1 (wire
407-PK) and contact 2 (wire 202-BK).
Expected Result:
The voltage is approximately 5 VDC.
Results:
• OK – The voltage is approximately 5 VDC.

• NOT OK – The voltage is not approximately 5

g01245812 VDC.
Illustration 82
Schematic of the torque converter oil temperature sensor Repair: There is a problem with the machine
harness or the ECU has failed. It is unlikely that
This diagnostic trouble code is associated with the ECU has failed.
the torque converter oil temperature sensor. This
diagnostic trouble code is recorded when the ECU Proceed to test step 2.
reads the voltage from the hydraulic oil temperature
sensor as being above normal. Test Step 2. CHECK FOR AN OPEN IN
THE SUPPLY CIRCUIT.
Possible causes of the diagnostic trouble code is
listed: A. The key start switch and the disconnect switch
remain in the ON position.
• The supply circuit to the sensor is open.
B. The sensor remains disconnected from the
• The return circuit is open. machine harness.
• The signal circuit is shorted to the +battery. C. At the machine harness connector for the sensor,
measure the voltage from contact 1 (wire 407-PK)
• The signal circuit is open or the sensor is to ground.
disconnected.
Expected Result:
The voltage is approximately 5 VDC.
Results:
• OK – The voltage measurement is approximately

5 VDC. Proceed to test step 3.
KENR5099-06 131
• NOT OK – The voltage does not measure D. Observe the status of the SPN 3823 FMI 3.
approximately 5 DC.
Expected Result:
Repair: The supply circuit is not correct. Repair
the circuit or replace the circuit. The diagnostic trouble code changes from FMI 3 to
STOP.
Results:
Test Step 3. CHECK FOR AN OPEN IN
THE RETURN CIRCUIT. • YES – The diagnostic trouble code remains active.
A. Turn the disconnect switch and the key start trouble code. Proceed to Test Step 5.
B. The sensor remains disconnected from the sensor has failed.
machine harness.
Repair: Replace the sensor. Verify that the new
C. Disconnect the machine harness connector J1 sensor corrects the problem.
from the ECU.
D. At the machine harness connector for the sensor,
install a jumper wire from contact 2 (wire 202-BK) Test Step 5. CHECK IF THE DIAGNOSTIC
to ground. TROUBLE CODE IS STILL ACTIVE.
E. At the machine harness connector for the ECU, A. Inspect the harness connectors. Clean the
measure the resistance from contact J1-21 (wire contacts of the harness connectors and check the
202-BK) to ground. wires for damage to the insulation that is caused
Expected Result:
The resistance measurement is less than 5000 ohms. wires that are associated with the circuit.
Results: C. Reconnect all harness connectors in order to

• OK – The resistance measurement is less than Also, make sure that the clips for each connector
5000 ohms. The harness is correct. are completely fastened.
Repair: The sensor has failed. Check the sensor. D. Turn the disconnect switch and the key start
• NOT OK – The resistance that is measured is not
correct. F. Determine if the SPN 3823 FMI 3 is active.
Repair: There is an open in the machine harness. Expected Result:

The open is in the return circuit with the high
resistance measurement. Repair the harness or The SPN 3823 FMI 3 is active.
replace the harness.
Results:
Test Step 4. CHECK THE SENSOR. diagnostic trouble code has not been corrected.
A. Turn the disconnect switch and the key start Repair: Check the circuit again. It is unlikely
switch to the ON position. Do not start the engine. that the ECU has failed. Replace the sensor. If
replacing the sensor does not correct the problem,
B. Disconnect the sensor with the active diagnostic replace the ECU. Prior to replacing an ECU, always
trouble code from the machine harness. contact your dealership for possible consultation
with Caterpillar. This consultation may greatly
C. At the machine harness connector for the sensor, reduce repair time. See Testing and Adjusting,
place a jumper wire from contact 2 (wire 202-BK) “Electronic Control Unit - Replace”.
to contact 1 (wire 407-PK).
STOP.
132 KENR5099-06
• NO – The SPN 3823 FMI 3 is not active. The Test Step 1. CHECK THE SENSOR
The initial diagnostic trouble code was probably A. Turn the disconnect switch and the key start
caused by a poor electrical connection or a switch to the ON position.
disconnected and reconnected. Resume normal B. Ensure that the diagnostic trouble code is active.
C. Observe the status of the diagnostic trouble code.
Disconnect the sensor from the machine harness.
i02482304
Transmission, SPN 3823 - FMI Expected Result:
4 The SPN 3823 FMI 4 remains active. The FMI has

not changed and the “04” is still active.
SMCS Code: 1439-038-VC; 3101-038-NS
Results:
• OK – The diagnostic trouble code remains active.
The sensor is correct. Proceed to Test Step 2.
• NOT OK – The diagnostic trouble code is no

longer active. The sensor has failed.
STOP.
Test Step 2. CHECK THE WIRING

HARNESS OF THE SENSOR FOR A
SHORT TO GROUND.
g01245812 A. Turn the key start switch and the disconnect

Illustration 83
Schematic of the torque converter oil temperature sensor
torque converter oil temperature sensor. The FMI 4 C. Disconnect the machine harness connector(s)
means that the ECU has determined that the voltage from the ECU.
of the circuit for the position sensor is below normal.
D. At the machine harness connector for the ECU,
The possible causes of this diagnostic trouble code measure the resistance from the signal contact
are listed below: J1-29 (wire 407-PK) of the machine harness
to all possible sources of ground. Measure the
• The signal circuit for the sensor is shorted to resistance to all contacts of the machine harness
ground. connectors for the ECU.
• The sensor has failed. Expected Result:
• The ECU has failed. This is unlikely. Each resistance measurement is greater than 5000
ohms.
other diagnostic trouble codes. Ignore these Results:
diagnostic trouble codes when the original diagnostic • OK – Each resistance measurement is greater
trouble code has been corrected. Ensure that the than 5000 ohms. The machine harness is correct.
diagnostic trouble code of SPN 3823 FMI 4 is Proceed to Test Step 3.
• NOT OK – One or more resistance measurements
Note: Use a digital multimeter for the measurements is not correct. There is a short in the machine
in this procedure. harness.
KENR5099-06 133
Repair: The short is between signal contact • NO – The SPN 3823 FMI 4 is not active. The
J1-29 (wire 407-PK) and the circuit with the low problem does not exist at this time. The initial
resistance measurement. Repair the machine diagnostic trouble code was probably caused by
harness or replace the machine harness. a poor electrical connection or a short at one of
STOP. reconnected. Resume normal machine operation.
STOP.
i02558599

wires for damage to the insulation that is caused 16
SMCS Code: 1439-038-VC; 3101-038-NS
wires that are associated with the circuit. Conditions Which Generate This Code:


Expected Result:
g01245812
Illustration 84
Schematic of the torque converter oil temperature sensor
Results:
• YES – The SPN 3823 FMI 4 is active. The problem torque converter oil temperature sensor. The FMI
has not been corrected. 16 means that the ECU has determined that the oil
temperature is above a normal operational range.
Repair: Check the circuit again. If the Caterpillar The temperature could cause severe damage. The
Electronic Technician (ET) is available, use the Cat ECU reads the resistance from the sensor. A high oil
ET service tool in order to perform a “Wiggle Test” temperature will send a low voltage to the ECU. The
on the machine wiring harness. The “Wiggle Test” high temperature sends a voltage that is lower than
can detect shorts and opens in the machine wiring the expected result for the ECU.
The cause of this diagnostic trouble code is listed:
procedure and perform this procedure again. If • The oil temperature has reached 121° ± 8°C
the cause of the diagnostic touble code is not (250° ± 14°F).
ECU, always contact your dealership for possible The possible causes of this diagnostic trouble code
consultation with Caterpillar. This consultation are listed:
Adjusting, “Electronic Control Unit - Replace”. • Excessive oil temperature
STOP.
134 KENR5099-06
System Response: Repair: Stop the engine until the oil temperature
returns to an acceptable range.
The vehicle is safe when the temperature of the oil
is below 121 °C (250 °F). Oil at this temperature is STOP.
in the green area on the gauge. Operators should
modify the operation of the vehicle in order to reduce Test Step 3. CHECK IF THE DIAGNOSTIC
the temperature of the oil as soon as possible TROUBLE CODE REMAINS.
when the temperature is between 121 °C (250 °F)
and 149 °C (300 °F). Oil at this temperature is in A. Inspect the harness connectors. Clean the
the yellow area on the gauge. Operating a vehicle contacts of the harness connectors and check the
can result in damage to the transmission when the wires for damage to the insulation that is caused
temperature of the oil is above 149 °C (300 °F). Oil at by excessive heat, battery acid, or chafing.
this temperature is in the red area on the gauge.
Test Step 1. INSPECT THE HARNESS wires that are associated with the circuit.
CONNECTIONS.
A. Turn the disconnect switch to the OFF position. that the harness connectors are fully seated and
B. Check the connectors for proper mating. fastened.
C. Check the wires at the connector. D. Turn the disconnect switch and the key start
D. Check each wire for nicks or signs of abrasion in
the insulation. E. Operate the vehicle.
E. Check for moisture at the connector. F. Check the status of the SPN 3823 FMI 16.
F. Check the connectors for dirty contacts or Expected Result:

corroded contacts.
G. Check each pin and each socket of the machine
harness connectors. Results:
Expected Result: • YES – The SPN 3823 FMI 16 is active. The

of corrosion. Repair: Check the circuit again. It is unlikely
Results: perform this procedure again. If the cause of the
• OK – The machine harness connectors are tight ECU. Prior to replacing an ECU, always contact
and free of corrosion. Proceed to test step 2. your dealership for possible consultation with
• NOT OK – The machine harness connectors are repair time. See Testing and Adjusting, “Electronic
in need of repair. Control Unit - Replace”.
Repair: Repair the machine harness or replace the STOP.

machine harness.
STOP. diagnostic trouble code does not exist at this time.
Test Step 2. VERIFY THE TEMPERATURE caused by a poor electrical connection at one of
OF THE OIL. the harness connectors that was disconnected and
Check the temperature of the oil. STOP.
Results:
• OK – The temperature of the oil is correct. Proceed

to Test Step 3.
• NOT OK – The temperature of the oil is not correct.

KENR5099-06 135
i02694515 Test Step 1. CHECK THE ENERGIZE

Transmission, SPN 3824 - FMI SHORT TO THE +BATTERY CIRCUIT.
3
SMCS Code: 5479-038-T3 switch to the OFF position.
Conditions Which Generate This Code: B. Disconnect the machine harness connectors from

X830-OR) to all contacts that are used in the
Expected Result:

ohms.
Results:
g01280782
Illustration 85 than 5000 ohms. The machine harness is correct.
Schematic of the transmission latching solenoid Proceed to Test Step 2.
This diagnostic trouble code is associated with the • NOT OK – Each resistance measurement is not
transmission latching solenoid. The FMI 3 means greater than 5000 ohms. There is a short in the
that the ECU has determined that the voltage of the machine harness. The short is between J1-48
solenoid circuit is above normal. (X830-OR) and the circuit that has a low resistance
measurement.
The possible causes of the diagnostic trouble code
are listed: Repair: Repair the machine harness or replace the
machine harness.
STOP.
the +battery circuit. Test Step 2. CHECK IF THE DIAGNOSTIC
Note: The following test procedure may create contacts of the harness connectors and check the
other diagnostic trouble codes. Ignore these wires for damage to the insulation that is caused
created diagnostic trouble codes and clear these by excessive heat, battery acid, or chafing.
trouble code has been corrected. Ensure that the B. Perform a 45 N (10 lb) pull test on each of the
diagnostic trouble code of SPN 3824 FMI 3 is wires that are associated with the circuit.
Note: Use a digital multimeter for the measurements make sure that the connectors are fully seated.
in this procedure. Also, make sure that the clips for each connector
System Response:
The transmission does not shift to NEUTRAL. Using switch to the ON position.
the shifter to select NEUTRAL does not shift the
transmission to NEUTRAL. E. Operate the machine.
Expected Result:

136 KENR5099-06

Repair: Check the circuit again. It is unlikely other diagnostic trouble codes. Ignore these
that the ECU has failed. Exit this procedure and created diagnostic trouble codes and clear these
perform this procedure again. If the cause of the diagnostic trouble codes when the original diagnostic
diagnostic trouble code is not found, replace the trouble code has been corrected. Ensure that the
ECU. Prior to replacing an ECU, always contact diagnostic trouble code of SPN 3824 FMI 5 is
your dealership for possible consultation with active before performing this procedure.
repair time. See Testing and Adjusting, “Electronic Note: Use a digital multimeter for the measurements
Control Unit - Replace”. in this procedure.
STOP. System Response:
• NO – The SPN 3824 FMI 3 is not active. The The transmission does not shift to NEUTRAL. Using
diagnostic trouble code does not exist at this time. the shifter to select NEUTRAL does not shift the
The initial diagnostic trouble code was probably transmission to NEUTRAL.
i02694517
Transmission, SPN 3824 - FMI trouble code from the machine harness.
5 C. At the machine harness connector for the

SMCS Code: 5479-038-T3 X830-OR) to contact 2 (wire 922-BR).
Conditions Which Generate This Code: D. Observe the status of the SPN 3824 FMI 5.
Expected Result:

Results:


g01280782 solenoid has failed.
Illustration 86
Schematic of the transmission latching solenoid Repair: The solenoid has failed. Replace the
This diagnostic trouble code is associated with the problem.
transmission latching solenoid. The FMI 5 means
that the ECU has determined that an open in the STOP.
circuit exists.
The possible causes of this diagnostic trouble code AN OPEN.
are listed below:
• The energize circuit of the solenoid is open. switch to the OFF position.

KENR5099-06 137
B. Disconnect the machine harness connector(s) Repair: Check the circuit again. If the Caterpillar
from the ECU. Electronic Technician (ET) is available, use the Cat
C. The jumper wire that was installed in the previous on the machine wiring harness. The “Wiggle Test”
Test Step remains in place. can detect shorts and opens in the machine wiring
D. At the machine harness connector, measure
the resistance from signal contact J1-48 (wire It is unlikely that the ECU has failed. Exit this
X830-OR) to contact J1-50 (wire 922-BR). procedure and perform this procedure again. If
Expected Result: found, replace the ECU. Prior to replacing an
The resistance is less than 5.0 ohms. consultation with Caterpillar. This consultation
Results: Adjusting, “Electronic Control Unit - Replace”.
• OK – The resistance is less than 5.0 ohms. The STOP.

3. • NO – The SPN 3824 FMI 5 is not active. The
• NOT OK – The resistance is greater than 5000 The initial diagnostic trouble code was probably
ohms. The resistance measurement is not correct. caused by a poor electrical connection or a
There is an open circuit in the machine harness. short at one of the harness connectors that was
Repair: Repair the machine harness or replace the machine operation. STOP.
machine harness.
i02694518
STOP.

TROUBLE CODE REMAINS. 6
A. Inspect the harness connectors. Clean the SMCS Code: 5479-038-T3
wires for damage to the insulation that is caused Conditions Which Generate This Code:


fastened.


g01280782
Illustration 87
Schematic of the transmission latching solenoid
Expected Result:
The SPN 3824 FMI 5 is active. transmission latching solenoid. The FMI 6 means
that the ECU has determined that there is a short to
Results: ground in the solenoid circuit.
• YES – The SPN 3824 FMI 5 is active. The The possible causes of this diagnostic trouble code
diagnostic trouble code has not been corrected. are listed:

ground.
138 KENR5099-06
• The solenoid has failed. D. At the machine harness connector, measure the
• The ECU has failed. This is unlikely. X830-OR) to all contacts that are used in the
other diagnostic trouble codes. Ignore these Expected Result:
diagnostic trouble codes when the original diagnostic Each resistance measurement is greater than 5000
trouble code has been corrected. Ensure that the ohms.
active before performing this procedure. Results:
Note: Use a digital multimeter for the measurements • OK – Each resistance measurement is greater
in this procedure. than 5000 ohms. The machine harness is correct.
System Response:
The transmission does not shift to NEUTRAL. Using greater than 5000 ohms. There is a short in the
the shifter to select NEUTRAL does not shift the machine harness. The short is between J1-48 (wire
transmission to NEUTRAL. X830-OR) and the circuit with the low resistance
measurement.
STOP.
C. Disconnect the solenoid with the active diagnostic TROUBLE CODE REMAINS.
The FMI 6 changes to FMI 5 when the solenoid is by excessive heat, battery acid, or chafing.
disconnected.
Results: wires that are associated with the circuit.
• YES – The FMI 6 changes to FMI 5 when the C. Reconnect all harness connectors. Make sure
solenoid is disconnected. The circuit is correct. that the harness connectors are fully seated and
Repair: The solenoid has failed. Replace the fastened.
problem. D. Turn the disconnect switch and the key start
STOP.
• NO – The SPN 3824 FMI 6 remains active.
Proceed to Test Step 2. F. Check the status of the SPN 3824 FMI 6.
Test Step 2. CHECK THE ENERGIZE Expected Result:

SHORT TO GROUND. The SPN 3824 FMI 6 is active.
A. Turn the key start switch and the disconnect Results:

B. The solenoid remains disconnected from the diagnostic trouble code has not been corrected.
machine harness.

from the ECU.
KENR5099-06 139
Repair: Check the circuit again. If the Caterpillar This sensor is a frequency sensor. The sensor sends
Electronic Technician (ET) is available, use the Cat a frequency to the ECU as the gear teeth pass the
ET service tool in order to perform a “Wiggle Test” magnet. The voltage is proportional to the speed of
on the machine wiring harness. The “Wiggle Test” the transmission output shaft. The frequency that is
can detect shorts and opens in the machine wiring sent to the ECU increases when the speed of the
harness that are momentary or intermittent. teeth increases.
It is unlikely that the ECU has failed. Exit this The possible causes of this diagnostic trouble code
procedure and perform this procedure again. If are listed below:
found, replace the ECU. Prior to replacing an • Intermittent connections or poor connections
consultation with Caterpillar. This consultation • The sensor is loose.
Adjusting, “Electronic Control Unit - Replace”. • The sensor has failed.
STOP. • The ECU has failed. This is unlikely.
• NO – The SPN 3824 FMI 6 is not active. The Note: The following test procedure may create
diagnostic trouble code does not exist at this time. other diagnostic trouble codes. Ignore these
The initial diagnostic trouble code was probably created diagnostic trouble codes and clear the
caused by a poor electrical connection at one of diagnostic trouble codes when the original diagnostic
the harness connectors that was disconnected and trouble code has been corrected. Ensure that
reconnected. Resume normal machine operation. the diagnostic trouble code of SPN 3825 FMI
STOP. 8 is active before performing this procedure.
The engine must be running in order for the
diagnostic trouble code to be active.
i02522230
Transmission, SPN 3825 - FMI Note: Use a digital multimeter for the measurements
in this procedure.
8
System Response:
SMCS Code: 3175-038-OJ
The ECU will use the other speed sensor in order to
Conditions Which Generate This Code: determine the speed of the transmission output shaft.

CONNECTIONS.

clean and tight.


g01262239 abrasion.
Illustration 88
Schematic of the transmission output speed sensor 2 E. Check the wires at the connector. Ensure that the
transmission output speed sensor 2. The FMI 8 F. Perform a 45 N (10 lb) pull test on each of the
means that the ECU has determined that the signal wires that are associated with the circuit. Take
frequency is not within the expected range. care not to pull the wire out of the connector.

H. Check for moisture inside the connector.

140 KENR5099-06
I. Check the connectors for dirty contacts or Test Step 3. CHECK THE SENSOR FOR
corroded contacts. AN OPEN.
J. Check each pin and each socket of the machine A. The disconnect switch and the key start switch
harness connectors. Ensure that the contacts remain in the OFF position.
correctly when the two pieces of the connector B. Remove the jumper wire that was used in the
are placed together. previous Test Step.
Expected Result: C. Remove the sensor from the machine harness.

Insert a multimeter probe in contact 1 and contact
The machine harness connectors are tight and free 2 of the sensor.
of corrosion.
Results:
Expected Result:
and free of corrosion. Proceed to test step 2. The resistance should be between 600 and 1800
ohms.
in need of repair. Results:
Repair: Repair the machine harness or replace the • YES – The resistance is between 600 and 1800
machine harness. ohms. The sensor is correct. Proceed to Test Step
4.
STOP.
Test Step 2. CHECK THE CIRCUIT FOR ohms. The sensor has failed.
AN OPEN.
switch to the OFF position. STOP.
B. Disconnect the machine harness from the sensor. Test Step 4. CHECK IF THE DIAGNOSTIC
install a jumper wire between contact 1 and A. Inspect the harness connectors. Clean the
contact 2 of the harness. contacts of the harness connectors and check the
D. Disconnect the machine harness connector J1 by excessive heat, battery acid, or chafing.
from the ECU.
E. At the J1 machine harness connectors for the wires that are associated with the circuit.
ECU, measure the resistance from contact J1-8
for the sensor to J1-9. C. Reconnect all harness connectors in order to
Expected Result: Also, make sure that the clips for each connector
There should be less than 5.0 ohms resistance.
Results: switch to the ON position.
• YES – The machine harness is correct. Proceed E. Operate the machine.

to Test Step 3.
harness. The open circuit is in the wire (E906-OR) Expected Result:
or in the wire (E907-GY) of the machine harness.
machine harness.
STOP.
KENR5099-06 141
Results:


STOP.

142 KENR5099-06
Testing and Adjusting Perform the following procedure in order to replace

the speed sensor.
Section
1. Turn the key start switch and the disconnect switch
to the OFF position. Disconnect the machine
harness connector from the sensor and remove
Testing and Adjusting the sensor.
2. By hand, install the new sensor into the housing of

i02492396 the gear until the sensor contacts the gear tooth.
Speed Sensor - Replace 3. Set the air gap of the sensor to 0.89 mm
SMCS Code: 1439-510-VF; 3141-510; 3175-510 (0.035 inch). The air gap is set by turning the
sensor 180 degrees in the counterclockwise
direction. For the output speed sensors, the air
Speed Sensor (1) (Transmission gap is preset.
Output) , Speed Sensor (2)
4. Tighten the sensor to 25 ± 5 N·m (18 ± 4 lb ft).
(Transmission Output), Engine Tighten the output speed sensors to 28 ± 7 N·m
Speed Sensor and Speed Sensor (21 ± 5 lb ft).
(Torque Converter Output) 5. Inspect the sensor connector of the machine
harness. Connect the machine harness to the
sensor.
6. Verify that the sensor corrects the problem.
i03387784
Transmission - Calibrate
SMCS Code: 3155-524
This procedure is used in order to optimize the quality

of shifts. The procedure must be performed under
the following conditions:
g00903616
Illustration 89
• Perform the procedure after installing a new
transmission.
• Perform the procedure after replacing the ECU or

servicing the ECU.
• Perform the procedure after exchanging the ECU

from one machine to another machine.
• Perform the procedure after replacing or servicing

any of the transmission clutches, seals, pumps,
etc.
g00585709
Illustration 90
Speed Sensor
Prior to replacement of the sensor, ensure that the

sensor has failed. Check the connection to the
sensor. Measure the voltage between the contacts
of the sensor. Check for metal shavings on the
magnetic tip or the gear teeth.
KENR5099-06 143
Transmission Calibration
g01370834
Illustration 91
Note: The following procedure will require the Table 32

machine to be driven. Shifting will be harsh at Display description
the beginning of the procedure. The quality of the
shifts will improve throughout the calibration of the “OL-LO-##” Oil level is low by “##
transmission. The quality of the shift will stabilize to a ”quarts.
consistent level as the calibration is completed. “OL-HI-##” Oil level is high by “##”
quarts.
1. Verify that the fluid in the transmission is at the
correct level. The transmission fluid level test is “OL-OK” Oil level is correct.
a manually initiated operation. The results are
indicated on the gearshift selector. The operator 2. Connect and open the Caterpillar Electronic
may initiate the fluid level test after the following Technician (Cat ET). Confirm a J1939 connection.
conditions are met. The vehicle must be level,
stationary, and idling. The vehicle must also have a 3. Click “Configuration” on the menu bar. Select
transmission fluid temperature of 80° C (176° F)at “Vehicle Configuration Parameters” from the
a minimum. Perform the following actions in order options on the left side. Click “Transmission
to initiate the test. Simultaneously press the Calibration Configuration” from the drop-down list.
up arrow and the down arrow. Simultaneously
release the up arrow and the down arrow. The 4. Program the calibration to “All Clutches”. See
gearshift selector will count down from 24. The figure 91 for more information.
results are displayed when the count is complete.
The table below shows the possible readings and 5. Cycle the power to the ECU. Turn the key start
the descriptions. switch from the ON position to the OFF position.
Now, turn the key start switch to the ON position.
144 KENR5099-06
6. Verify that the oil temperature of the transmission 11. Perform shifts from fifth gear to fourth gear by
is in a normal range. A normal range is above stepping through the shift for the CX28 and
60 °C (140 °F) and below 100 °C (212 °F). the CX31. This type of shift is achieved by
The calibration will not begin until the oil accelerating the transmission to the fifth gear. The
temperature reaches 60 °C (140 °F). machine will downshift to the fourth gear during
the acceleration. Allow the vehicle to coast in the
7. Complete this step before leaving the lot. With the fifth gear to the shift point from fifth gear to fourth
parking brake RELEASED and the service brake gear. Do not apply the throttle. The range for the
APPLIED, shift the transmission from NEUTRAL shift point is 1200 to 1400 RPM on an engine that
to DRIVE. Shift the transmission from NEUTRAL has a 1200 RPM peak torque. The range for the
to REVERSE. Repeat these shifts until there is shift point is 1300 to 1600 RPM on an engine that
no noticeable change in quality of the shift or a has a 1440 RPM peak torque. Repeat these shifts
minimum of five times. You may leave the lot once until there is no noticeable change in the quality of
this step is completed. the shifts or for a minimum of five times.
Note: See this note for the CX35 only when Note: If the quality of shifting remains poor after this
the feature for starting in an alternate gear is procedure, refer to the Troubleshooting, “Symptom
programmed to 2. The Alternate Start Gear function Troubleshooting” section for more information.
will shift the transmission from first gear to second
gear when drive is selected on the shifter. The feature
i02492390
will resume normal operation after the calibration
procedure is completed. Electrical Connector - Inspect
8. Move the vehicle to a safe place. Accelerate the SMCS Code: 7553-040-WW
machine up to the second gear for the CX28 and
the CX31. Maintain the engine speed at 1200 to Use this procedure under the following situation:
1300 RPM. A series of shifts from second gear to
first gear will be performed by the transmission Use the following steps to help determine if the
in four second intervals. Do NOT release the connector is the cause of the problem. If a problem is
throttle. Maintain this condition until the shifts found in the electrical connector, repair the connector
have stopped. Repeat these shifts until there is no and verify that the problem has been corrected.
noticeable change in the quality of the shifts or for
a minimum of three times. The following background information is related
to this procedure:
9. With both of the brakes RELEASED, perform
the following shifts to the transmission and allow Many of the operational procedures and the
the machine to move. Sustain the throttle at diagnostic trouble code procedures in this
approximately fifty percent and perform the shifts. troubleshooting guide will instruct you to check a
Upshift the transmission from first gear through specific electrical connector.
fifth gear for the CX28 and the CX31. Upshift the
transmission from first gear through seventh gear Intermittent electrical problems are often caused
for the CX35. by poor connections. Always check for an active
diagnostic trouble code before breaking any
10. Downshift the transmission from fifth gear through connections. Also, always check for an active
first gear while the machine is coasting for the diagnostic trouble code after the connector is
CX28 and the CX31. Downshift the transmission reconnected in order to verify that the problem
from seventh gear through first gear while the disappears.
machine is coasting for the CX35. Braking slightly
is permitted. Simply disconnecting the connectors and then
reconnecting the connectors can temporarily solve
Note: Avoid using all of the brakes or retarders.service a problem at times. If this occurs, likely causes are
brake, hydraulic retarder, and engine brake. loose terminals, bent terminals, improperly crimped
terminals, corrosion, or harness routing that is
improper.
The original source of the problem must then be

identified in order to ensure that the problem does
not reoccur.
Follow this procedure to thoroughly inspect the

connectors in order to determine if the connectors
are the cause of the problem.
KENR5099-06 145
g00820688
Illustration 92
(1) Correctly Routed Harness (3) Incorrectly Routed Harness
(2) Correctly Inserted Plug (4) Incorrectly Inserted Plug
g00690571 g00828600
Illustration 93 Illustration 94
Proper Installation of Plug DT Type sealing plug
The 8T-8729 Connector Pin (2) and the 8T-8730 Connector
Socket (1) is designed to accept only one 16/18 AWG wire. Do not
insert multiple wires of a smaller wire size. Using two 24 AWG
wires is an example of this method that is incorrect. The 9W-0852
Connector Pin and the 9W-0844 Connector Socket is designed
to accept only one 14 AWG wire. Do not insert multiple wires of a
smaller wire size. Using two 20 AWG wires is an example of this
method that is incorrect.
146 KENR5099-06
1. CHECK THE CONNECTORS. a. Each connector contact should withstand 45 N

(10 lb) of pull. Each wire should remain in the
a. Ensure that the connector is properly locked. connector body. This test checks whether the
Also, ensure that the two halves of the wire was properly crimped in the contact and
connector can not be pulled apart. whether the contact was properly inserted into
the connector.
b. Verify that the latch tab of the connector is
properly latched. Verify that the latch tab of the b. The DT connectors use an orange wedge to
connector is fully latched. lock the terminals in place.
Expected Result: The connector will securely c. Check in order to ensure that the orange wedge
lock. The connector and the locking mechanism is not missing and that the orange wedge is
are without cracks or breaks. installed properly on the DT connectors.
Results: Note: Connector contacts should ALWAYS be

crimped onto the wires by using a Crimp Tool. Do not
OK – The connector will securely lock. The solder the terminals. Use the proper Crimp Tool.
connector and the locking mechanism are
without cracks or breaks. Proceed to test step Expected Result: Each connector contact
2. should withstand 45 N (10 lb) of pull. Each wire
remains in the connector body.
NOT OK – A problem exists with the connector.
Results:
Repair: Repair the connector or replace the
connector, as required. OK – Each connector contact withstands
45 N (10 lb) of pull. Each wire remains in the
STOP. connector body. Proceed to test step 4.
2. CHECK THE ALLEN HEAD SCREW ON THE NOT OK – A problem exists with the connector.
HARNESS CONNECTOR OF THE ECU.
Repair: Repair the wiring or replace the
a. Ensure that the connector bolt is properly connector contact.
tightened. Be careful not to tighten the bolt too
much. The bolt may break. STOP.
b. Do not exceed 6.0 N·m (53.0 lb in) of torque 4. CHECK THE WIRES FOR NICKS OR
on the connector bolt of the harness when the ABRASIONS IN THE INSULATION.
connector is being installed on the ECU.
a. Carefully inspect each wire for signs of
Expected Result: The harness connector is abrasion, nicks, or cuts.
secure and the connector bolt of the ECU is
properly torqued. The following areas are locations that should
be checked:
Results:
• Exposed insulation
OK – The harness connector is secure and
the connector is properly torqued. Proceed to • Points of rubbing wire
test step 3.
b. Check all of the hold down clamps for the
NOT OK – A problem exists with the connector. harness in order to verify that the harness is
properly clamped. Also check all of the hold
Repair: Secure the harness connector of the down clamps for the harness in order to verify
ECU. Ensure that the connector bolt is properly that the harness is not compressed by the
torqued. clamp. Pull back the harness sleeves in order
to check for a flattened portion of wire. The
STOP. flattened portion of wire is caused by the clamp
that holds the harness.
3. PERFORM A PULL TEST ON EACH
CONNECTOR CONTACT. Expected Result: The wires are free of
abrasion, nicks, or cuts and the harness is
properly clamped.
Results:
KENR5099-06 147
OK – The wires are free of abrasion, nicks, Results:

or cuts and the harness is properly clamped.
Proceed to test step 5. OK – All of the connectors are completely
coupled and all of the seals are completely
NOT OK – A problem exists with the wiring. inserted. The harness and the wiring are free of
corrosion, moisture, abrasions or pinch points.
Repair: Repair the wires or replace the wires, Proceed to test step 6.
as required.
NOT OK – A problem exists with the connector,
STOP. the wiring or the wiring harness. Moisture is
present.
5. CHECK THE CONNECTORS FOR MOISTURE
OR CORROSION. Repair: Repair the connectors or wiring and/or
replace the connectors or wiring. Ensure that
a. Ensure that the connector seals and the white all of the seals are properly in place and ensure
sealing plugs are in place. If any of the seals or that the connectors are completely coupled.
plugs are missing, replace the seal or plug. If Verify that the repair eliminates the problem by
necessary, replace the connector. operating the machine for several minutes and
by checking again for moisture.
b. Check all of the wiring harnesses in order to
verify that the harness does not make a sharp STOP.
bend out of a connector. This will deform the
connector seal and this will create a path for 6. INSPECT THE CONNECTOR CONTACTS.
the entrance of moisture. See Illustration 92.
a. Verify that the contacts are not damaged.
Note: It is normal to see some minor seal abrasion Verify that the contacts are properly aligned in
on the ECU connector seals. Minor seal abrasion will the connector and verify that the contacts are
not allow the entry of moisture. properly located in the connector.
c. Thoroughly inspect ECU connectors for Expected Result: The contacts are properly
evidence of moisture entry. If moisture or aligned and the contacts appear undamaged.
corrosion is evident in the connector, the
source of the moisture entry must be found Results:
and the source of the moisture entry must be
repaired. If the source of the moisture entry is OK – The contacts are properly aligned and
not repaired, the problem will reoccur. Simply the contacts appear undamaged. Proceed to
drying the connector will not fix the problem. test step 7.
Likely paths for the entrance of moisture are
from missing seals, improperly installed seals, NOT OK – A problem exists with the connector
nicks in exposed insulation, and improperly contacts.
mated connectors.
Repair: Repair the contacts and wiring and/or
Note: Moisture can also travel from one connector replace the contacts and wiring.
through the inside of a wire to the ECU Connector. If
moisture is found in the ECU connector, thoroughly STOP.
check all connectors and wires on the harness that
connect to the ECU. The ECU is not the source of the 7. CHECK THE FIT OF THE CONTACTS.
moisture. Do not replace an ECU if moisture is found
in either ECU connector.
Note: If corrosion is evident on the contacts or the

connector, use only denatured alcohol to remove
the corrosion. Use a cotton swab or a soft brush
to remove the corrosion. Do not use cleaners that
contain trichloro-ethylene because trichloro-ethylene
may damage the connector.
Expected Result: All of the connectors should

be completely coupled and all of the seals
should be completely inserted. The harness
and the wiring should be free of corrosion,
moisture, abrasion or pinch points.
148 KENR5099-06
OK – The pin contacts and the socket contacts

appear to be OK. STOP.
NOT OK – A problem exists with the connector

terminal.
Repair: Replace the connector contact.
STOP.
i02492400
Wiring Harness (Open Circuit)

- Test
SMCS Code: 1408-081
An open is a failure of an electrical circuit that

results in no flow of electrical current. An open
circuit is usually caused by failed electrical wires
or a poor connection of electrical connectors. If an
electrical wire or a connection is broken, the flow of
electrical current through the circuit is interrupted. A
normally closed circuit will have less than 5 ohms of
resistance. The following procedure explains the test
for an open circuit:
Reference: For a complete electrical schematic,

refer to Electrical System Schematic for the machine
that is being serviced.
TEST FOR AN OPEN CIRCUIT.
g00838765 1. Identify the connectors and the wire numbers of

Illustration 95
the suspect circuits. Use the Electrical System
Retention of the Connector Schematic of the machine to identify the circuits.
(1) Pin Contact
(2) Socket Contact 2. Turn the key start switch and the disconnect
Note: This is especially important for intermittent
problems. 3. Disconnect the component and the ECU from the
wiring harness.
a. Use a new pin contact. Insert the pin contact
into each socket contact one at a time in order 4. At one of the disconnected harness connections,
to check for a good grip on the pin contact by place a jumper wire from the contact of the
the socket contact. suspect wire to frame ground.
b. Use a new socket contact. Insert the socket 5. At the other connector of the machine harness,
contact over each pin contact one at a time use the multimeter probes to measure the
in order to check for a good grip on the pin resistance from the contact of the suspect wire to
contact by the socket contact. The pin contact frame ground.
are located on the mating side of the connector.
Expected Result: The resistance is less than 5
c. The connector contact should stay connected ohms.
when the connector is held in the position
shown in Illustration 95. The connector contact OK – The resistance is less than 5 ohms. The
is the pin contact or the socket contact. harness circuit is correct.
Expected Result: The pin contacts and the Stop.
socket contacts appear to be OK.
NOT OK – The resistance is greater than 5000
Results: ohms. There is an open in the machine harness.
KENR5099-06 149
Repair: Repair the machine harness or replace Repair: Repair the machine harness or replace
the machine harness. the machine harness.
Stop. Stop.
i02492401 i02492392
Wiring Harness (Short Circuit) Electronic Control Unit - Flash

- Test Program
SMCS Code: 1408-081 SMCS Code: 7610-591-DTN
A short circuit is a failure of an electrical circuit that Table 33

results in undesired electrical current. Usually, a Required Tools
short circuit is a bypass of the circuit across a load.
For example, a short across the wires in a circuit for WinFlash Software
a lamp produces too much current in the wires but
no current is felt at the lamp. The lamp is shorted Perform the following procedures to flash program
out. The resistance in a normal circuit can vary, but an ECU. The ECU is flashed in order to upgrade
the resistance between a particular circuit and other software. The ECU is flashed in order to load
unrelated circuits is always greater than 5 ohms. software into an ECU. Flash programming of an ECU
The following procedure explains the test for a short must also be done if the ECU has been replaced.
circuit: The Caterpillar Electronic Technician (ET) contains
the program WinFlash. WinFlash is used to load
Reference: For a complete electrical schematic, software into the ECU. The following procedure is
refer to Electrical System Schematic for the machine used in order to flash software into an ECU.
that is being serviced.
1. Connect the 7x-1425 Data Link Cable between
TEST FOR A SHORT CIRCUIT. the 7x-1700 Communication Adapter and the ET.
1. Identify the connectors and the wire numbers of 2. Connect the 139-4166 Data Link Cable between
the suspect circuits. Use the Electrical System the 7x-1700 Communication Adapter and the
Schematic of the machine to identify the circuits. diagnostic connector of the machine.
2. Turn the key start switch and the disconnect 3. Use WinFlash to load the new software.
Note: The ECU will indicate that the ECU is “BLANK”
3. Disconnect the component and the ECU from the if the ECU is blank or an unsuccessful “FLASH” was
wiring harness. performed.
4. At the machine harness connector for the ECU,
place one of the multimeter probes on the contact i03627543
of the suspect wire.
Electronic Control Unit -
5. Use the other multimeter probe to check the Configure
resistance across all other contacts in the
connector(s) of the ECU and frame ground. SMCS Code: 7610-025-DTN
Expected Result: The resistance is greater than

5000 ohms for all the measurements. Machine Configuration
Table 34
OK – The resistance is greater than 5 ohms for
all the measurements. The harness circuits are Required Tools
correct. Part Number Description Quantity
Stop. JEBD3003 Caterpillar Electronic 1

Technician (Cat ET )
NOT OK – The resistance is less than 5 ohms. 171-4401 Communications 1
There is a short in the machine harness. The short Adapter II
is between the suspected wire and the wire with
the lowest resistance measurement. 207-6845 Adapter Cable As 1
160-0141 Adapter Cable As 1
150 KENR5099-06
The Caterpillar Electronic Technician (Cat ET) is i03627550

the service tool that is used in order to access the
configuration screen . A message on the Cat ET Electronic Control Unit -
screen will give instructions that guide the user Replace
through the procedure. Refer to the Manual that
is provided with the Cat ET software for more SMCS Code: 7610-510-DTN
information about Cat ET.
Prior to the replacement of the ECU, ensure that
replacement is necessary. The ECU is seldom
the cause of a failure. Always check that power is
available to all of the contacts of the ECU that are
marked with “+ Battery”.
Note: Corrupted configuration software or the wrong

software may cause an ECU to incorrectly report
diagnostic trouble codes. Prior to replacing the ECU,
flash the ECU with the correct configuration software
in order to verify that the failure is not related to
corrupted software. See Testing and Adjusting,
“Electronic Control Unit - Flash Program”.
Procedure
1. Connect the Caterpillar Electronic Technician (Cat

ET). Note all configurations.
2. Turn the disconnect switch and the key start

g01248379
Illustration 96
This is a typical view of the service connector for the Data Link. 3. Disconnect the machine harness connectors from
the ECU.
The Transmission ECU must be configured when
the Transmission ECU has been replaced. The 4. Verify that the part number of the replacement
configuration screen is only for machines with a ECU. ECU is correct.
The ECU needs to be configured before a calibration
can be started. 5. Install the replacement ECU.
A check of the configuration screen could resolve 6. Connect the machine harness to the ECU.
a problem with the machine. A problem with a
component could be identified as one of the following 7. Turn the disconnect switch and the key start
items: switches to the ON position.
• The component is not installed. 8. Check for correct configurations. If necessary, use
the Cat ET to install the configuration software.
• The component is installed but a change to the Refer to the Testing and Adjusting, “Electronic
installation is needed in order to correct a problem. Control Unit - Flash Program” section of this
manual.
Follow these instructions to get to the configuration
screen: 9. Clear any diagnostic trouble codes that were
caused by the previous procedures.
1. Connect the communications adapter and the
computer to the diagnostic service tool connector. 10. Verify that the ECU operates correctly.
2. Start the Cat ET.
3. Select “File”. Go to “Select ECU”. Choose the

“Transmission ECU”.
4. Go to the “Service” Menu. Select “Configuration”.

Click “OK”. Certain operations or characteristics
can be changed for attachments or preferences.
KENR5099-06 151
i03122923
System Schematic
SMCS Code: 7566-T3
See the entire electrical system schematic of

the machine for more information. The entire
schematic illustrates every component and the wire
connections. All of the wiring harnesses that are
important to troubleshooting and repair are illustrated
on the electrical schematic. The part number of the
components is listed in addition to the number for
the harnesses.
Refer to Electrical Schematic, KENR5884 for

the complete electrical schematic of the CX28
Transmission.

Transmission.

Transmission.
152 KENR5099-06
g01425599
Illustration 97
Connections of the J1 connector for CX28
KENR5099-06 153
g01425601
Illustration 98
154 KENR5099-06
g01371046
Illustration 99
KENR5099-06 155
g01432693
Illustration 100
156 KENR5099-06
g01371090
Illustration 101
KENR5099-06 157
g01346286
Illustration 102
158 KENR5099-06
Index Section
Index
A Input Components ................................................. 27
Bypass Switch (Transmission Filter) .................. 30
Additional Functions .............................................. 14 Engine Speed Sensor ........................................ 28
Alternate Start In Gear Driver Output................. 16 Key Start Switch................................................. 30
Backup Alarm Driver Output Function ............... 14 Oil Level Sensor (Transmission) ........................ 28
Fail In Gear ........................................................ 16 Sensors.............................................................. 27
Gear Driver Output Indicator.............................. 15 Switches............................................................. 30
Parking Brake .................................................... 14 Torque Converter Temperature Sensor.............. 28
Retarder ............................................................. 15 Transmission Oil Temperature Sensor............... 28
Service Brake Operation.................................... 14 Transmission Output Speed Sensor (1) and
Shift Display Blank Input Function ..................... 15 Transmission Output Speed Sensor (2) ........... 29
Shift Selection Function ..................................... 15 Transmission Output Speed Sensor (Torque
Starter Interlock Driver Output Function ............ 14 Converter) ........................................................ 29
Introduction............................................................ 35
C
O
Connector Locations.............................................. 36
Harness Connectors .......................................... 37 Output Components .............................................. 31
OEM Connector ................................................. 38 Output Drivers.................................................... 31
Solenoids ........................................................... 31
D
P
Data Link ............................................................... 32
SAE J1587 ......................................................... 34 Programmable Parameters ................................... 16
SAE J1939 ......................................................... 32
Determining Diagnostic Trouble Codes ................. 44
Using Caterpillar Electronic Technician to R
Determine Diagnostic Trouble Codes .............. 44
Diagnostic Capabilities .......................................... 39 Replaced Relay or Solenoid Does Not Operate .... 42
Status Groups For The Cat ET .......................... 40
The Caterpillar Electronic Technician (Cat ET) .. 39
Diagnostic Trouble Code List ................................ 43 S
Diagnostic Trouble Code Procedures.................... 43
Service Tools ......................................................... 35
Speed Sensor - Replace ..................................... 142
E Speed Sensor (1) (Transmission Output) , Speed
Sensor (2) (Transmission Output), Engine Speed
Electrical Connector - Inspect.............................. 144 Sensor and Speed Sensor (Torque Converter
Electronic Control Unit........................................... 23 Output) ........................................................... 142
Input/Output ....................................................... 27 Symptom Troubleshooting..................................... 41
Inputs ................................................................. 27 System Protection Functions................................. 12
Outputs .............................................................. 27 Check Transmission Lamp ................................ 13
Electronic Control Unit - Configure ...................... 149 Directional Shift Management Function ............. 13
Machine Configuration ..................................... 149 Engine Overspeed Protection ............................ 13
Electronic Control Unit - Flash Program .............. 149 Fan Control for High Transmission Oil
Electronic Control Unit - Replace ........................ 150 Temperature ..................................................... 14
Engine Does Not Crank......................................... 41 Power Down Function........................................ 12
Speed Enable Output......................................... 13
Starter Interlock Output Function ....................... 12
G Tattletale Function.............................................. 13
Torque Limiting Function.................................... 13
General Information........................................... 4, 35 Transmission Filter Bypass Function ................. 12
General Operation ............................................... 5 Warning Lamp.................................................... 13
System Schematic............................................... 151
Systems Operation Section ..................................... 4
I
Important Safety Information ................................... 2

KENR5099-06 159
Index Section
T Transmission, SPN 734 - FMI 6 ............................ 82

Table of Contents..................................................... 3 Transmission, SPN 735 - FMI 5 ............................ 85
Testing and Adjusting .......................................... 142 Transmission, SPN 735 - FMI 6 ............................ 87
Testing and Adjusting Section ............................. 142 Transmission, SPN 736 - FMI 3 ............................ 88
Transmission - Calibrate...................................... 142 Transmission, SPN 736 - FMI 5 ............................ 89
Transmission Calibration ................................. 143 Transmission, SPN 736 - FMI 6 ............................ 91
Transmission Control............................................. 19 Transmission, SPN 737 - FMI 3 ............................ 92
Basic Operation ................................................. 21 Transmission, SPN 737 - FMI 5 ............................ 94
Transmission Does Not Automatically Shift Back Into Transmission, SPN 737 - FMI 6 ............................ 95
Gear..................................................................... 41 Transmission, SPN 738 - FMI 3 ............................ 97
Transmission Does Not Automatically Shift Into Transmission, SPN 738 - FMI 5 ............................ 98
Neutral ................................................................. 41 Transmission, SPN 738 - FMI 6 ............................ 99
Transmission Does Not Respond to Shift Transmission, SPN 739 - FMI 3 .......................... 101
Selector................................................................ 42 Transmission, SPN 739 - FMI 5 .......................... 102
Transmission Shifting Function ............................... 6 Transmission, SPN 739 - FMI 6 .......................... 104
Alternate Maximum Gear Function .................... 10 Transmission, SPN 740 - FMI 3 .......................... 105
Auto Neutral Function .......................................... 6 Transmission, SPN 740 - FMI 5 .......................... 106
Direction Shift Inhibit Function ............................. 7 Transmission, SPN 740 - FMI 6 .......................... 108
Driveline PTO Mode............................................. 8 Transmission, SPN 744 - FMI 3 .......................... 109
Economy Shift Mode........................................... 11 Transmission, SPN 744 - FMI 5 ........................... 111
Elevated Downshift Function ............................. 10 Transmission, SPN 744 - FMI 6 ........................... 114
Hold Input Function............................................. 11 Transmission, SPN 91 - FMI 19 ............................ 50
Lockup Clutch Function ....................................... 8 Transmission, SPN 91 - FMI 9 .............................. 48
Neutral To Gear Inhibit Function .......................... 9 Transmission, SPN 973 - FMI 19 ......................... 117
Quick Gear Limit ................................................. 11 Transmission, SPN 973 - FMI 9 ........................... 115
Rapid Downshift Function .................................. 10 Troubleshooting Section........................................ 35
Shifter Selection Function ................................... 11
Top Gear Function ............................................. 10
Transmission PTO Control Selection ................. 10 W
Transmission, SPN 126 - FMI 3 ............................ 51 Wiring Harness (Open Circuit) - Test................... 148
Transmission, SPN 158 - FMI 2 ............................ 54 Wiring Harness (Short Circuit) - Test ................... 149
Transmission, SPN 1716 - FMI 13 ...................... 120
Transmission, SPN 1716 - FMI 8 ......................... 118
Transmission, SPN 3823 - FMI 16 ...................... 133
©2010 Caterpillar Cat, Caterpillar, their respective logos, “Caterpillar Yellow” and the Power edge Printed in U.S.A.
All Rights Reserved trade dress, as well as corporate and product identity used herein, are trademarks
of Caterpillar and may not be used without permission.

KENR5099 06检修

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KENR5099-06

Important Safety Information

The meaning of this safety alert symbol is as follows:

When replacement parts are required for this

Failure to heed this warning can lead to prema-

Table of Contents Transmission, SPN 736 - FMI 3 ............................ 88

Systems Operation Section

The Transmission ECU electronically interrelates with Transmission ECU

• Transmission Sump Temperature Sensors Shift Selector

The following electronic control modules • Transmission at operating temperature

Oil Filter Bypass Pressure Switch • Pressure sensors

Table 1 If the direction inhibit function is programmed to OFF,

• DPTO Request DPTO and Parking Brake Interaction - The

PTO Mode Maximum Engine Speed for Hold Input Function

Quick Gear Limit Function Customer Parameter

Engine Overspeed Protection Warning Lamp

The feature can be used in order to disable vehicle • Installed

Starter Interlock Driver Output

Retarder Shift Enable Switch Alternate Start In Gear Driver

Retarder Dual Switch

Retarder Mode Programmable Parameters

Parameter Available Range/Options Default

Equipment Identification Parameters

(Table 10, contd)

Parameter Available Range/Options Default

Disabled, Enabled for Forward,

(Table 10, contd)

Parameter Available Range/Options Default

Not Configured, Mode Button Input,

i03358020 There is an optional gearshift selector. This gearshift

When the transmission control is in the NEUTRAL

Press the neutral lock switch, and move the

“R” – The “R” indicates the reverse gear. Pressing

“N” – The “N” indicates the transmission neutral

“D” – The “D” button indicates the forward gears.

“Mode” – Mode Selector

Stop the vehicle and ensure that the engine is at low

(5) “N” button A downshift inhibitor prevents the operator from

Once the desired gear is selected, the transmission

Note: The transmission will not shift into a gear from

Push the “R” button in order to select the reverse

Note: 4 shows that the transmission is in first gear

Circumstances that prevent shifting into the desired

• The engine speed is too high.

The “MODE” button is available to control a variety

Oil Level Check

• The vehicle is stationary. i02861821

• Transmission oil temperature is more than 80 °C Electronic Control Unit

Table 11 J1-2 Engine Speed Sensor +

Display Description J1-3 Engine Speed Sensor −

OL-TX- N Neutral is not selected. J1-6 Transmission Output Speed A +

OL-OT-LO Oil temperature is too low. J1-7 Transmission Output Speed A −

OL-OT-HI Oil temperature is too high. J1-8 Transmission Output Speed B +

OL-VS-HI Vehicle speed is not zero. J1-9 Transmission Output Speed B −

J2-13 Speed Enable Output J1-11 Oil Level Sensor Power

J2-14 Switch to Battery 1 J1-13 − Battery

J2-19 Output Speed Driver J1-20 J1587 -

J2-26 Quick Gear Limit Switch J1-21 Sensor Return

J2-29 Parking Brake Switch J1-23 − Battery