CAT EP18-20NT Troubleshooting Manual

TROUBLESHOOTING FOR CONTROL CIRCUITS
General Information
Before replacing devices

Do not replace devices immediately even if replacement is required as a result of troubleshooting. Be sure to check
the following items before replacing devices (logic unit, logic card, power supply card, inverters, inverter DSP cards,
input unit and output unit).
• Loose of battery connectors
• Abnormal of wire harness connections
• Loose of connectors
• Broken, bent or loose of connector pins
• Dirty connectors
If connectors are dirty, remove the connector and clean connectors.
See "How to clean harness connectors and system components" on page 2-2.
• Ensure that the main harness is not short-circuited to the truck body by using the following procedures.
Disconnect battery plug and discharge the inverters before

working on electrical system.
Disconnect connector CN4 of logic unit. Check continuity between

CN4-15(21) and truck body (logic unit installation bolts, etc.).
No continuity Continuity
Normal Repair or replace harness.
If any of these items (above items) is a source of the trouble, the device will be damaged even if it is replaced with a
new one. Be sure to check the above items and carefully replace.
Connection of the service tool Error code display

1. Turn off the truck power.
2. Remove floor plates.
3. Find the connector to the service tool near the logics
unit.
4. Remove the cover and connect the PC as shown.
5. Turn on the truck power.
6. Start the service tool software.
211331
2-1
How to clean harness connectors and system

components
1. Open-circuits are often caused by dirty harness
connectors and components in dirty condition. Dust,
together with greasy matter, forms grime which, in
time, penetrates electrical connections, resulting in
loose metal-to-metal contact or, for worse, electrical
separation of surfaces in contact. For this reason, it is
essential that the connectors and components be
cleaned at each periodic inspection and at when
servicing the truck. Instead of a commonly used
solvent, use electronic parts cleaner (in the manner
illustrated on the right).
Electronic parts cleaner
211223
Electronic parts
Three Bond 29B
cleaner
NOTE
The cleaner liquid is volatile. All you have to do is just
give a strong spray to wash off grime.
No need to wipe off the sprayed liquid.
2. After checking the connector for continuity, wash it as

shown. Then, uncouple the connector and spray contact
surface activator onto contact surfaces. Install and
remove the connector several times to wet the surfaces
thoroughly with the activator liquid. After coupling up
Electronic parts
the connector, check to be sure that it is in locked state. cleaner
Contact surface Three Bond 2501S

activator (aerosol)
NOTE
Do not spray too much liquid into the connector.
Cleaner liquid reacts differently with some resins
(plastic materials).
Contact surface
activator
205047
2-2
Problem: Traction Motor R.H., Overheating (E0)

(1) Situation
Controller/motor overheat indicator ON. Poor pulling power and acceleration.
Normal pump motor and power steering operations. Service tool "Alarm status" and "E0" displayed.
(2) Possible cause

Overheating of right traction motor, faulty right traction motor or thermal sensor, faulty or open harness wiring,
faulty right traction inverter DSP card, abnormal power supply of logic unit, brake or parking brake drag,
abnormality in front axle, faulty display unit.
(3) How the error code is triggered.

Motor temperature is out of range of -25 °C to 145 °C (-13 °F to 293 °F).
It becomes normal when motor temperature is less than 70 °C (158 °F).
(4) Checks
Let truck cool for 15 minutes.
Overheat indicator ON Overheat indicator OFF
(5) Traction motor becomes normal.
If problem recurs
(6) Disconnect battery plug. Disengage brake
and parking brake, and check their drag.
No drag Drag
(7) Adjust brake.
(8) Lift front wheels, and disengage parking brake.

Turn key switch to OFF, rotate front wheels.
Confirm there is no difference in rotation load
between right and left wheels.
No difference Difference
(9) Check if truck is operated on steep

upgrade or to pull large cargo load.
Normal
(10) Perform inverter discharging work. See page 1-41.
(11) Replace right traction (12) Replace right traction

motor. motor or front axle.
See Chassis & Mast. See Chassis & Mast.
With service tool
(13) Confirm temperature of right traction motor with

Without service tool input/output monitor.
70 °C(158 °F) or more Less than 70 °C(158 °F)
(14) Disconnect battery plug. Wait until right traction motor (15) Disconnect battery plug.
temperature becomes close to room temperature.
2-3
(16) Perform inverter discharging work. See page 1-41. (17) Replace display unit. See Chassis & Mast.
(18) Disconnect connector CN14 of right traction motor

speed and thermal sensor. Measure resistance
between CN14(124) and (125) at motor side.
6kΩ at 40°C (104°F) to
19kΩ at 10°C (50°F) Out of range
Thermal
(19) Disconnect connector CN7 of right traction inverter. (20) Replace right traction motor. See Chassis & Mast.
Check continuity between CN7-1 and CN14(125).
Continuity No continuity
Power supply
(21) Check continuity between CN4-3 and CN7-17(252).
Check continuity between CN4-6 and CN7-20(255).
CAN
(22) Disconnect connector CN3 of logic unit.
Check continuity between CN3-5(211) and CN7-3(224).
(23) Connect connector CN4, then turn on power again. (24) Repair or replace harness.
(25) Measure voltage between CN7-17(252) and

CN7-20(255). Confirm value is 14V±2V.
Normal Abnormal
(26) Disconnect battery plug.
(27)Replace power supply card of logic unit. See page 1-48.

With service tool
Without service tool
(28) Ensure all connectors are connected. Check Run
Time Diagnosis data. See page 1-39.
The latest data is "E0". Not "E0"
(29) Disconnect battery (30)Disconnect battery plug.

plug, then perform Replace display unit.
inverter discharging
work. See page 1-41.
(31)Replace DSP card of right traction inverter. See page 1-44.
2-4
Logic
CN3 CN7 Traction inverter (right)
BG 0 to 5V V
CAN 5 WP 211 0 to 5V
224
L
3 Inside Inside
6 212 229 4 of of
O cover case
14
O
15
5 WG 254 12V R 16 P Fuse
R 252 14V RP
Power 3 R 253 8V RL
17
N Battery (-)
4 18 DSP IMS
B 255 GND B 20 card card
6 U IUR
5V * 1 Y 1
Power card GND G V IVR
2 Flat
CN4 12V Y
5 cable W IWR
0 to 5V Y 6
0 to 5V B
7
GND O 19
CN14 Traction motor (right)

O 127 Speed
B sensor W TWR
Y
146
M U TUR
145 TVR
Y V
126
G Thermal
124 sensor
Y 125 283Ω to 163kΩ
1: With connector disconnected
*
211224
2-5
Problem: Traction Motor L.H., Overheating (E1)

(1) Situation
(2) Possible cause

Overheating of left traction motor, faulty left traction motor or thermal sensor, faulty or open harness wiring, faulty
left traction inverter DSP card, abnormal power supply of logic unit, brake or parking brake drag,
abnormality in front axle, faulty display unit.

(4) Checks
(5) Traction motor becomes normal.
If problem recurs
(6) Disconnect battery plug. Disengage brake
and parking brake, and check their drag.
No drag Drag
(7) Adjust brake.
(8) Lift front wheels, and disengage parking brake.

Turn key switch to OFF, rotate front wheels.
Confirm there is no difference in rotation load
between right and left wheels.
No difference Difference
(9) Check if truck is operated on steep
upgrade or to pull large cargo load.
Normal
(11) Replace left traction (12) Replace left traction

motor. motor or front axle.
See Chassis & Mast. See Chassis & Mast.
With service tool
(13) Confirm temperature of left traction motor with

(14) Disconnect battery plug. Wait until left traction motor (15) Disconnect battery plug.
2-6
(18) Disconnect connector CN15 of left traction motor

between CN15(129) and (130) at motor side.
6kΩ at 40°C (104°F) to
Thermal
(19) Disconnect connector CN6 of left traction inverter. (20) Replace left traction motor. See Chassis & Mast.
Power supply
(21) Check continuity between CN4-3(252) and CN6-17(260).
CAN
(22)Disconnect connector CN3 of logic unit.

Normal Abnormal
(27) Replace power supply card of logic unit. See page 1-48.
With service tool

(29) Disconnect battery (30) Disconnect battery plug.

(31) Replace DSP card of left traction inverter. See page 1-44.
2-7
Logic
CN3 CN6 Traction inverter (left)
BG 0 to 5V V 3
224
L 4 Inside Inside
6 212 229 of of
cover case
14
15
WG 254 12V 259 RY
5 16 P Fuse
R 252 14V 260 RGr 17
Power 3 R 8V 261 R 18 N Battery (-)
4 253 DSP IMS
B 255 GND 262 B card
6 20 card U IUL
5V * 1 Y 1
Power card GND G V IVL
2
CN4 12V V 5 Flat
cable W IWL
0 to 5V L
6
0 to 5V G
7
GND O 19
CN15 Traction motor (left)

O 132 Speed
G sensor W TWL
L
148
M U TUL
147 TVL
V
V 131 Thermal
G 129 sensor
Y 130 283Ω to 163kΩ
*1: With connector disconnected
211225
2-8
Problem: Pump Motor, Overheating (E2)

(1) Situation
Controller/motor overheat indicator ON. Lifting speed slower than normal. Normal traction motor
and power steering operations. Service tool "Alarm status" and "E2" displayed.
(2) Possible cause

Overheating of pump motor, faulty pump motor or thermal sensor, faulty or open harness wiring, faulty pump
motor inverter DSP card, abnormal power supply of logic unit, abnormal oil pressure of gear pump or
hydraulic lines, faulty display unit.

(4) Checks
(5) Pump motor becomes normal.
If problem recurs
(6) Check if truck is operated to lift large cargo load.
Normal
(8) Check oil pressure of gear pump and hydraulic lines.

Normal Abnormal
(9) Replace pump motor. (10)Repair or replace gear

See Chassis & Mast. pump or piping.
With service tool See Chassis & Mast.
(11) Confirm temperature of pump motor with

(12) Disconnect battery plug. Wait until pump motor (13) Disconnect battery plug.
(16) Disconnect connector CN20 of pump motor

between CN20(134) and (135).
6kΩ at 40°C (104°F) to
Thermal
(17) Disconnect connector CN5 of pump motor inverter. (18) Replace pump motor. See Chassis & Mast.
2-9
Power supply
CAN

Normal Abnormal
(24)Disconnect battery plug.
With service tool
(26)Ensure all connectors are connected. Check Run
(27) Disconnect battery (28) Disconnect battery

plug, then perform plug. Replace display
inverter discharging unit.
(29) Replace DSP card of pump motor inverter. See page 1-44.
2-10
Logic
CN3 CN5 Pump inverter
BG 0 to 5V V
234
L
3 Inside Inside Pump contactor
6 212 239 4 of of
O cover case F
14
O Fuse
15
5 WG 254 12V 265 RG 16 P
R 14V 266 RY
Power 3 R 252 8V 267 RW
17
N Battery (-)
4 253 18 DSP IMS
B 255 GND 268 B 20 card card
6 U IU
5V* 1 RB 1
Power card GND W V IV
2 Flat
CN4 12V L
5 cable W IW
0 to 5V R 6
0 to 5V Y
7
GND V 19
CN20 Pump motor

V 138 Speed
Y sensor W PW
R
137
M U PU
136 PV
L V
133 Thermal
W 134 sensor
R 135 160Ω to 163kΩ
1: With connector disconnected
*
211226
2-11
Problem: Traction Inverter R.H., Overheating (E5)

(1) Situation
(2) Possible cause

Overheating of right traction inverter, faulty right traction inverter thermal sensor, open harness wiring, faulty
right traction inverter PC board, abnormal power supply of logic unit, faulty radiation of right traction
inverter, faulty display unit.

Controller temperature is out of range of -25 °C to 100 °C (-13 °F to 212 °F).
Capacitor temperature is out of range of -25 °C to 110 °C (-13 °F to 230 °F).
It becomes normal when temperature is less than 70 °C (158 °F).
(4) Checks
(5) Right traction inverter becomes normal.
If problem recurs
(6) Check if truck is operated on steep upgrade or to pull
large cargo load.
Normal
Check thermal paste applied on inverter mounting
surface. Thermal paste film should be thin and even.
Normal Abnormal
(8) Replace right traction (9) Clean mounting surface,

inverter. See page 1-42. apply thermal paste,
With service tool then reinstall inverter.
See page 1-42.
(10)Confirm temperature of controller and head capacitor

Without service tool with input/output monitor.
(11) Disconnect battery plug. Wait until inverter (12) Disconnect battery plug.
(14) Replace display unit. See Chassis & Mast.

Thermal
(15) Remove right traction inverter DSP card cover, then
check harness looseness or wire breakage. See page 1-44.
Normal Abnormal
Power supply
(16) Disconnect connector CN7 of right traction inverter. (17) Secure harness if loose.
Check continuity between CN4-3 and CN7-17(252). Replace inverter if wire breaks. See page 1-42.
2-12
CAN
(19)Connect connector CN4, then turn on power again. (20) Repair or replace harness.

Normal Abnormal
With service tool
(25) Disconnect battery (26)

plug, then perform Disconnect battery plug.
inverter discharging Replace display unit.
(27) Replace DSP card of right traction inverter. See page 1-44.
If fault remains
(28) Disconnect battery plug, then perform inverter
discharging work. See page 1-41.
(29)Replace right traction inverter. (DSP card is normal.)

See page 1-42.
2-13
Logic
BG 0 to 5V V
224
L
3 Inside Inside
6 212 229 4 of of
O cover case
14
O
15
5 WG 254 12V R 16 P Fuse
R 252 14V RP
Power 3 R 253 8V RL
17
N Battery (-)
4 18 DSP IMS
6 U IUR
1
Power card Controller V IVR
2 Flat thermistor
CN4
5 cable W IWR
6
7 Capacitor
thermistor
19

DSP flat 127 Speed
cable sensor W TWR
Inverter
146
M U TUR
145 TVR
case V
126
Thermal
DSP card 124 sensor
125
211227
2-14
Problem: Traction Inverter L.H., Overheating (E6)

(1) Situation
(2) Possible cause

Overheating of left traction inverter, faulty left traction inverter thermal sensor, open harness wiring, faulty
left traction inverter PC board, abnormal power supply of logic unit, faulty radiation of left traction
inverter, faulty display unit.

(4) Checks
(5) Left traction inverter becomes normal.
If problem recurs
(6) Check if truck is operated on steep upgrade or to pull
large cargo load.
Normal
Normal Abnormal
(8) Replace left traction (9) Clean mounting surface,

inverter. See page 1-42. apply thermal paste,
then reinstall inverter.
With service tool See page 1-42.
(10) Confirm temperature of controller and head

Without service tool capacitor with input/output monitor.
(11)Disconnect battery plug. Wait until inverter (12)Disconnect battery plug.

(13) Perform inverter discharging work. See page 1-41. (14)Replace display unit. See Chassis & Mast.
Thermal
(15)Remove left traction inverter PC board cover, then
check harness looseness or wire breakage. See page 1-44.
Normal Abnormal
Power supply
(16)Disconnect connector CN6 of left traction inverter. (17) Secure harness if loose.
Check continuity between CN4-3(252) and CN6-17(260). Replace inverter if wire breaks. See page 1-42.
2-15
CAN

Normal Abnormal
With service tool
(25) Disconnect battery (26) Disconnect battery plug.

(27)Replace DSP card of left traction inverter. See page 1-44.
If fault remains
(28)Disconnect battery plug, then perform inverter
(29)Replace left traction inverter. (DSP card is normal.)

See page 1-42.
2-16
Logic
BG 0 to 5V V 3
224
L 4 Inside Inside
6 212 229 of of
cover case
14
15
WG 254 12V 259 RY
5 16 P Fuse
R 14V 260 RGr 17
Power 3 R 252 8V 261 R 18 N Battery (-)
4 253 DSP IMS
6 20 card U IUL
1
Power card Controller V IVL
2 thermistor
CN4 Flat
5 cable W IWL
6
Capacitor
7 thermistor
19

DSP flat 132 Speed
cable sensor W TWL
Inverter
148
M U TUL
147 TVL
case V
131
Thermal
DSP card 129 sensor
130
211228
2-17
Problem: Pump Inverter, Overheating (E7)

(1) Situation
Controller/motor overheat indicator ON. Lifting speed slower than normal. Normal traction motor
and power steering operations. Service tool "Alarm status" and "E7" displayed.
(2) Possible cause

Overheating of pump inverter, faulty pump inverter thermal sensor, open harness wiring, faulty pump inverter
PC board, abnormal power supply of logic unit, faulty radiation of pump inverter, faulty display unit.

(4) Checks
(5) Pump inverter becomes normal.
If problem recurs
(6) Check if truck is operated to lift large cargo load.
Normal
Normal Abnormal
(8) Replace pump inverter. (9)Clean mounting surface,

See page 1-42. apply thermal paste, then
With service tool reinstall inverter.
See page 1-42.
(10) Confirm temperature of controller and head
capacitor with input/output monitor.
(11) Disconnect battery plug. Wait until inverter (12) Disconnect battery plug.
Thermal
(15) Remove pump inverter DSP card cover, then check
harness looseness or wire breakage. See page 1-44.
Normal Abnormal
Power supply
(16) Disconnect connector CN5 of pump inverter. (17) Secure harness if loose.
2-18
CAN
(19) Connect connector CN4, then turn on power again. (20)Repair or replace harness.

Normal Abnormal
With service tool

(25) Disconnect battery (26)Disconnect battery plug.

(27)Replace DSP card of pump inverter. See page 1-44.
If fault remains

(29)Replace pump inverter. (DSP card is normal.)

See page 1-42.
2-19
Logic
BG 0 to 5V V
234
L
6 212 239 4 of of
O cover case F
14
O Fuse
15
5 WG 254 12V 265
RG 16 P
R 14V RY
Power 3 R 252 8V
266
RW
17
N Battery (-)
4 253 267 18 DSP IMS
6 U IU
1
Power card Controller V IV
2 Flat thermistor
CN4
5 cable W IW
6
Capacitor
7 thermistor
19
CN20 Pump motor

DSP flat 138 Speed
cable sensor W PW
Inverter
137
M U PU
136 PV
case V
133 Thermal
DSP card 134 sensor
135
211229
2-20
Problem: Brake Oil, Low Level

(1) Situation
Lower brake oil indicator ON. Normal truck operation.
(2) Possible cause

Insufficient brake oil, faulty brake oil level sensor, shorted wiring, faulty logic unit, faulty display unit.

Sensor signal is open or short.
(4) Checks
Check oil level in brake oil reservoir tank.
Normal Abnormal
(5) Add brake oil. See Chassis & Mast.
With service tool
Without service tool (6) Confirm brake oil level switch with input/output
monitor.
ON OFF
(7) Disconnect battery plug, then perform inverter (8) Disconnect battery plug. Replace display unit.
discharging work. See page 1-41. See Chassis & Mast.
(9) Disconnect connectors CN2 and CN3 of logic unit and

CN11 of sensor. Check continuity between CN11(139)
and CN11(140) at harness side.
(10) Check continuity of brake oil level sensor connector

coupled to CN11. (11) Repair or replace harness.
(12) Replace brake oil level sensor.

With service tool
Without
service tool
(13) Replace display unit. See Chassis & Mast.
If fault remains
(15) Reinstall display unit and replace logic card of logic

unit. See page 1-47.
2-21
Logic Logic
CN2 CN3
38 23
0V/12V GND
O L
139 140
CN11
O L
Brake fluid
sensor
211230
2-22
Problem: Traction Motor Current Sensor R.H. Fault (14)

(1) Situation
Display: "14". All truck operations inhibited. This fault occurs only when turning on power. Line contactor OPEN
and pump contactor HOLD.
(2) Possible cause

Faulty contact or wire breakage of DSP flat cable in right traction inverter, faulty DSP card of right traction
inverter, faulty right traction inverter, faulty main harness, faulty logic unit.

When turning on power, current sensor voltage is out of range of -120 A to 120 A.
(4) Checks
Disconnect battery plug, then perform inverter discharging work. See page 1-41.
(5) Disconnect connector CN7 of right traction inverter

and remove DSP cover. Check DSP flat cable for
looseness or wire breakage.
Normal Abnormal
8V power
supply
(6) Check continuity between CN4-4 and CN7-18(253). (7) Secure DSP flat cable if loose.
Continuity Abnormal and No continuity
CAN
Continuity Abnormal and No continuity
(9) Connect connector CN4 to logic unit, then turn on (10)Repair or replace harness.
power again.

Normal Abnormal
(12) Disconnect battery plug, then perform inverter discharging work. See page 1-41.
(13)Replace DSP card of right traction inverter. See page 1-44. (14) Replace power supply card of logic unit. See page 1-48.
If fault remains
(15) Perform inverter discharging work, then replace

right traction inverter. (DSP card is normal.)
See page 1-42.
2-23
Logic
BG 0 to 5V V
224
L
3 Inside Inside
6 212 229 4 of of
O cover case
14 U current sensor
O
15
5 WG 254 12V R 16 P Fuse
R 252 14V RP
Power 3 R 253 8V RL
17
N Battery (-)
4 18 DSP IMS
6 U IUR
1
Power card V IVR
2 Flat
CN4
5 cable W IWR
6
V current sensor
7
19

DSP flat 127 Speed
cable sensor W TWR
Inverter
146
M U TUR
145 TVR
case V
126
Thermal
DSP card 124 sensor
125
211231
2-24
Problem: Traction Motor R.H., Over-current (15)

(1) Situation Display: "15". Traction motor operation inhibited. Pump motor and power steering operations inhibited
if this fault occurs before pump contactor CLOSE, and both operable if it occurs after pump contactor
CLOSE. Line contactor OPEN and pump contactor CLOSE or OPEN.
(2) Possible cause

Faulty contact or wire breakage of DSP flat cable in right traction inverter, faulty DSP card of right traction
inverter, faulty right traction inverter, faulty right traction motor, faulty contact or wire breakage of right
traction motor speed sensor harness, faulty main harness, faulty logic unit.

Motor current is more than 1000 A (Moment). Motor current is more than 788 A (Fixed time 1).
Motor current is more than 696 A (Fixed time 2).
(4) Checks
(5) Check right traction motor and terminal for burning

and smell.
Normal Abnormal
(6) Confirm cable looseness and improper connections

(U, V, W phases) for right traction inverter and motor. (7) Replace right traction motor. See page 3-4.
Normal Abnormal

(9) Secure cable if loose or connect cable correctly.
Normal Abnormal
(10) Confirm connection of right traction motor speed (11) Secure DSP flat cable if loose.
sensor connector CN14. Replace inverter if wire breaks. See page 1-42.
Normal Abnormal
Sensor
(12) Disconnect connectors CN7 and CN14. (13) Connect connector securely.
8V power
supply
CAN
power again.
2-25

Normal Abnormal
(19) Disconnect battery plug, then perform inverter discharging work.
If fault remains
(22)Perform inverter discharging work, then replace right

traction inverter. (DSP card is normal.) See page 1-42.
If fault remains
(23)Perform inverter discharging work, then reinstall right
traction inverter and replace right traction motor.
2-26
Logic
BG 0 to 5V V
224
L
3 Inside Inside
6 212 229 4 of of
O cover case
14
O
15
5 WG 254 12V R 16 P Fuse
R 252 14V RP
Power 3 R 253 8V RL
17
N Battery (-)
4 18 DSP IMS
6 U IUR
1
Power card V IVR
2 Flat
CN4 12V Y
5 cable W IWR
0 to 5V Y
6
0 to 5V B
7
GND O 19

DSP flat O 127 Speed
cable B sensor W TWR
Inverter Y
146
M U TUR
145
case Y V TVR
126
Thermal
DSP card 124 sensor
125
211232
2-27
Problem: Traction Motor R.H., Stall Timer (16)

(1) Situation
Display:"16". Traction motor operation inhibited. Pump motor and power steering operations inhibited
(2) Possible cause

Stall current flowed more than set time (#20) in right traction motor, faulty right traction inverter current sensor,
shorted harness wiring, faulty right traction inverter DSP card, faulty logic unit.

Stall timer set time (set by Setup Option #20) is measured while stalling.
(4) Checks
Turn off power, then turn on power again. Confirm error code display.
No error, problem recurs Error code 14
(5) Confirm stall timer set time of Setup Option #20.

(6) See troubleshooting for code "14". See page 2-23.
Maximum value set Larger value can be set
(7) Check to see if truck is operated with heavy cargo (8) Change set time. See page 1-24.
load or on steps when motor stalls.
Note: The more stall occurs, the more overheating
Normal steeps Heavy load
occurs. Operate truck under normal condition.

(10) Operate under normal condition.

and remove DSP cover, then check DSP flat cable for
looseness or wire breakage. See page 1-44.
Normal Abnormal
Power supply
(12) Check continuity between CN4-5 and CN7-16(254). (13) Secure harness if loose. Replace right traction
Check continuity between CN4-6 and CN7-20(255). inverter if wire breaks. See page 1-42.
CAN
Continuity Abnormal and no continuity
(15)Connect connector CN4 to logic unit, then turn on (16)Repair or replace harness.
power again.

Normal Abnormal
(19) Replace DSP card of right traction inverter. See page 1-44. (20)Replace power supply card of logic unit. See page 1-48.
2-28
Logic
BG V
CAN 5 WP 211 224
L
3 Inside Inside
6 212 229 4 of of
O cover case
14 U current sensor
O
15
5 WG 254 12V R 16 P Fuse
R 252 14V RP
Power 3 R 253 8V RL
17
N Battery (-)
4 18 DSP IMS
6 U IUR
1
Power card V IVR
2 Flat
CN4
5 cable W IWR
6
V current sensor
7
19
127 Speed
sensor W TWR
146
M U TUR
145 TVR
V
126
Thermal
124 sensor
125
211233
2-29
Problem: Traction Motor Current Sensor L.H. Fault (24)

(1) Situation
Display: "24". All truck operations inhibited. This fault occurs only when turning on power.
Line contactor OPEN and pump contactor OPEN.
(2) Possible cause

Faulty contact or wire breakage of DSP flat cable in left traction inverter, faulty DSP card of left traction
inverter, faulty left traction inverter, faulty main harness, faulty logic unit.

(4) Checks
(5)Disconnect connector CN6 of left traction inverter and

remove DSP cover. Check DSP flat cable for looseness
or wire breakage.
Normal Abnormal
8V power
supply
(6) Check continuity between CN4-4(253) and CN6-18(261). (7) Secure DSP flat cable if loose.
CAN
(9) Connect connector CN4 to logic unit, then turn on

(10) Repair or replace harness.
power again.
(11)Measure voltage between CN6-18(261) and

Normal Abnormal
(12)Disconnect battery plug, then perform inverter discharging work. See page 1-41.
(13) Replace DSP card of left traction inverter. See page 1-44. (14) Replace power supply card of logic unit. See page 1-48.
If fault remains
(15) Perform inverter discharging work, then replace left

2-30
Logic
BG 0 to 5V V 3
CAN 5 WP 211
0 to 5V
224
L 4 Inside Inside
6 212 229 of of
cover case
14 U current sensor
15
WG 254 12V 259 RY
5 16 P Fuse
R 14V 260 RGr 17
4 253 DSP IMS
6 20 card U IUL
1
Power card V IVL
2
CN4 Flat
5 cable W IWL
6
V current sensor
7
19

DSP flat 132 Speed
cable sensor W TWL
Inverter
148
M U TUL
147 TVL
case V
131 Thermal
DSP card 129 sensor
130
211234
2-31
Problem: Traction Motor L.H., Over-current (25)

(2) Possible cause

Faulty contact or wire breakage of DSP flat cable in left traction inverter, faulty DSP card of left traction inverter,
faulty left traction inverter, faulty left traction motor, faulty contact or wire breakage of left traction motor speed
sensor harness, faulty main harness, faulty logic unit.

(4) Checks
(5) Check left traction motor and terminal for burning

and smell.
Normal Abnormal
(6) Confirm cable looseness and improper connections

(U, V, W phases) for left traction inverter and motor. (7) Replace left traction motor. See page 3-4.
Normal Abnormal
(8) Disconnect connector CN6 of left traction inverter and

or wire breakage.
Normal Abnormal
(10) Confirm connection of left traction motor speed (11) Secure DSP flat cable if loose.
sensor connector CN15. Replace inverter if wire breaks. See page 1-42.
Normal Abnormal
Sensor
(12) Disconnect connectors CN6 and CN15. (13) Connect connector securely.
8V power
supply
(14)Check continuity between CN4-4(253) and CN6-18(261).
CAN
power again.
2-32
(18)Measure voltage between CN6-18(261) and

Normal Abnormal
(19) Disconnect battery plug, then perform inverter discharging work.
If fault remains

If fault remains
(23) Perform inverter discharging work, then reinstall left
traction inverter and replace left traction motor.
2-33
Logic
BG 0 to 5V V 3
224
L 4 Inside Inside
6 212 229 of of
cover case
14 U current sensor
15
WG 254 12V 259 RY 16
5 P Fuse
R 14V 260RGr 17
Power 3 R 252 8V 261 R 18 DSP N Battery (-)
4 253 IMS
6 20 card U IUL
1
Power card V IVL
2
CN4 12V V 5 Flat
cable W IWL
0 to 5V L 6
0 to 5V G V current sensor
7
GND O 19

DSP flat O 132 Speed
cable G sensor W TWL
Inverter L
148
M U TUL
147 TVL
case V
V 131 Thermal
DSP card 129 sensor
130
211235
2-34
Problem: Traction Motor L.H., Stall Timer (26)

(1) Situation
Display:"26". Traction motor operation inhibited. Pump motor and power steering operations inhibited
(2) Possible cause
Stall current flowed more than set time (#20) in left traction motor, faulty left traction inverter current sensor,
shorted harness wiring, faulty left traction inverter DSP card, faulty logic unit.

Stall timer set time (set by Setup Option #20) is measured while stalling.
(4) Checks
No error, problem recurs Error code 24
(5) Confirm stall timer set time of Setup Option #20.

Maximum value set Larger value can be set
(7) Check to see if truck is operated with heavy cargo (8) Change set time. See page 1-24.
load or on steps when motor stalls. Note: The more stall occurs, the more overheating
Normal steeps Heavy load occurs. Operate truck under normal condition.
(9) Disconnect battery plug, then perform inverter (10) Operate under normal condition.

remove DSP cover, then check DSP flat cable for
looseness or wire breakage. See page 1-44.
Normal Abnormal
Power supply
(12) Check continuity between CN4-5(254) and CN6-16(259). (13) Secure harness if loose. Replace left traction
Check continuity between CN4-6(255) and CN6-20(262). inverter if wire breaks. See page 1-42.
CAN
Continuity Abnormal and no continuity
power again.

Normal Abnormal
(19) Replace DSP card of left traction inverter. See page 1-44. (20)Replace power supply card of logic unit. See page 1-48.
2-35
Logic
BG 0 to 5V V 3
224
L 4 Inside Inside
6 212 229 of of
cover case
14 U current sensor
15
WG 254 12V 259 RY
5 16 P Fuse
R 14V 260 RGr 17
4 253 DSP IMS
6 20 card U IUL
1
Power card V IVL
2
CN4 Flat
5 cable W IWL
6
V current sensor
7
19
132 Speed
sensor W TWL
148
M U TUL
147 TVL
V
131 Thermal
129 sensor
130
211236
2-36
Problem: Pump Motor Current Sensor Fault (34)

(1) Situation
Display: "34". All truck operations inhibited. This fault occurs only when turning on power.
(2) Possible cause

Faulty contact or wire breakage of DSP flat cable in pump inverter, faulty DSP card of pump
inverter, faulty pump inverter, faulty main harness, faulty logic unit.

(4) Checks
(5) Disconnect connector CN5 of pump inverter and

or wire breakage.
Normal Abnormal
8V power
supply
Check continuity between CN4-6(255) and CN5-20(268). Replace pump inverter if wire breaks. See page 1-42.
CAN
(9) Connect connector CN4 to logic unit, then turn on (10) Repair or replace harness.
power again.

Normal Abnormal
(13) Replace DSP card of pump inverter. See page 1-44. (14) Replace power supply card of logic unit. See page 1-48.
If fault remains
pump inverter. (DSP card is normal.) See page 1-42.
2-37
Logic
BG 0 to 5V V U current sensor
234
L
6 212 239 4 of of
O cover case F
14
O Fuse
15
5 WG 254 12V 265
RG 16 P
R 14V RY
Power 3 R 252 8V
266
RW
17
N Battery (-)
4 253 267 18 DSP IMS
6 U IU
1
Power card V IV
2 Flat
CN4
5 cable W IW
6
V current sensor
7
19
CN20 Pump motor

DSP flat Speed
cable 138
sensor W PW
Inverter
137
M U PU
case 136 PV
V
133 Thermal
DSP card 134 sensor
135
211237
2-38
Problem: Pump Motor Over-current (35)

(1) Situation
Display: "35". All truck operations inhibited.
(2) Possible cause

Faulty contact or wire breakage of DSP flat cable in pump inverter, faulty DSP card of pump inverter,
faulty pump inverter, faulty pump motor, faulty contact or wire breakage of pump motor speed sensor harness,
faulty main harness, faulty logic unit.

(4) Checks
(5) Check pump motor and terminal for burning and smell.
Normal Abnormal
(6) Confirm cable looseness and improper connections (U,

V, W phases) for pump inverter and motor. (7) Replace pump motor. See page 3-4.
Normal Abnormal

or wire breakage.
Normal Abnormal
(10) Confirm connection of pump motor speed sensor (11) Secure DSP flat cable if loose.
connector CN20. Replace pump inverter if wire breaks. See page 1-42.
Normal Abnormal
Sensor
(12) Disconnect connectors CN5 and CN20.
(13) Connect connector securely.
8V power
supply
(14)Check continuity between CN4-4(253) and CN5-18(267).
CAN

power again.
2-39

Normal Abnormal
(20) Replace DSP card of pump inverter. See page 1-44. (21)Replace power supply card of logic unit. See page 1-48.
If fault remains
If fault remains
(23) Perform inverter discharging work, then reinstall
pump inverter and replace pump motor.
2-40
Logic
0 to 5V U current sensor
BG V
234
L
6 212 239 4 of of
O cover case F
14
O Fuse
15
5 WG 254 12V 265
RG 16 P
R 14V RY
Power 3 R 252 8V
266
RW
17
N Battery (-)
4 253 267 18 DSP IMS
6 U IU
1
Power card V IV
2 Flat
CN4 12V L
5 cable W IW
0 to 5V R 6
0 to 5V Y V current sensor
7
GND V 19
CN20 Pump motor

DSP flat V 138 Speed
cable Y sensor W PW
Inverter R
137
M U PU
136
case L V PV
133 Thermal
DSP card 134 sensor
135
211238
2-41
Problem: Line Contactor Fault (40)

(1) Situation
(2) Possible cause

Faulty line contactor, faulty main harness, faulty logic unit, faulty right traction inverter, faulty left traction
inverter.

Inverter voltage data is checked when contactor is closed (400 mS).
(4) Checks
Error code 40 Error code 63 or 64
(5) Block wheels, then confirm line contactor (6) See troubleshooting for code "63" or "64". See page
operation in self-diagnosis mode [14]. See page 1-38. 2-80 or 2-82.
Not operated Operated
With service tool
(7) Check DC voltage of right and left traction (8) Disconnect battery plug, then perform
inverters with monitor. These values should be inverter discharging work. See page 1-41.
same as battery voltage.
Right inverter value Left inverter value
abnormal abnormal
(11) Replace right traction inverter.
See page 1-42.
(9) Disconnect battery (10) Disconnect battery
plug, then perform plug, then perform If fault remains
inverter discharging inverter discharging
work. See page 1-41. work. See page 1-41. (14) Disconnect battery plug, then perform
inverter discharging work. See page 1-41.
(12)Replace right traction (13) Replace left traction
inverter. See page 1-42. inverter. See page 1-42.
(15)Replace left traction inverter. See page 1-42.
(17) Check to see if line contactor tip moves smoothly.

Check line contactor tip for melting.
Normal Abnormal
(18) Measure resistance of contactor coil.

[44Ω at -30 °C(-22 °F) to 65Ω at 80 °C(176 °F)]
Within range Out of range
(19) Disconnect connectors CN1 and CN4 of logic unit.

Check continuity between CN4-13(4) and contactor (20) Replace line contactor. See Chassis & Mast.
coil plus(+)(249). Check continuity between CN1-59
and contactor coil minus(-)(247).
(21) Perform inverter discharging work, then replace logic

card of logic unit. See page 1-47.
2-42
Logic
CN7
CN3
BG 0 to 5V V Traction inverter
5 211 224 3
CAN 0 to 5V L (right)
6 WP 212 229 4 P
CN6
V
224 3 Traction inverter
L (left) P
229 4
Logic
CN1
voltage
-
Output 59 G 247
Line
Power card
contactor
R +
CN4 13 4 249
27V to battery
voltage
Fuse
211239
2-43
Problem: Pump Contactor Fault (42)

(1) Situation
(2) Possible cause

Faulty pump contactor, faulty main harness, faulty logic unit, faulty pump inverter.

Inverter voltage data is checked when contactor is closed (400 mS).
(4) Checks
Error code 42 Error code 65
(5) Block wheels, then confirm pump contactor

operation in self-diagnosis mode [15]. See page 1-38.
Not operated Operated
(8) Check to see if pump contactor tip moves smoothly. (9) Replace pump inverter. See page 1-42.
Check pump contactor tip for melting.
Normal Abnormal
(10) Measure resistance of contactor coil.

[44Ω at -30 °C(-22 °F) to 65Ω at 80 °C(176 °F)]
Within range Out of range

(12)Replace pump contactor. See Chassis & Mast.
Check continuity between CN4-13(4) and contactor
coil plus(+)(250). Check continuity between CN1-60
and contactor coil minus(-)(248).

logic card of logic unit. See page 1-47.
2-44
Logic
CN3 CN5
BG 0 to 5V V
5 211 234 3
CAN WP 0 to 5V L Pump inverter
6 212 239 4 P
Fuse
F
Logic
CN1 27V to battery
voltage
-
Output 60 B 248
R
Pump
Power card 27V to battery contactor
voltage
R R +
CN4 13 4 250
211332
2-45
Problem: Traction Motor R.H. Open (45)

(1) Situation
Display: "45". Traction motor operation inhibited. Pump motor and power steering operations inhibited
(2) Possible cause

Faulty contact or wire breakage of right traction motor cable, faulty right traction motor, faulty contact or wire
breakage of right traction inverter connector, faulty contact of DSP flat cable in right traction inverter, wire
breakage of main harness, faulty power supply card of logic unit, faulty DSP card of right traction inverter,
faulty right traction inverter, when restarting after motor shorted.

Motor voltage is abnormal when power is turned on.
Current does not flow when torque instruction is requested.
(4) Checks
(5) Check right traction inverter and motor for cable

looseness and improper contact.
Normal Abnormal
(6) Disconnect right traction motor cables from inverter.

(7) Secure cable if loose.
Measure resistance of motor cables
(U. V and W phases).
Less than 1Ω 1Ω or more
(8) Check connector CN7 of right traction inverter for (9) Measure resistance between terminals of both cable
looseness. ends (between U and U, V and V, and W and W).
Normal Abnormal Less than 1Ω 1Ω or more
(10) Disconnect connector CN7 of right

traction inverter and remove DSP
cover. Check DSP flat cable for
Normal Abnormal (12) Replace right traction motor. (13) Replace motor cables.
Gate power
supply
(14) Check continuity between CN4-5 and CN7-16(254). (15) Secure DSP flat cable if loose.
CAN
power again.
2-46

Normal Abnormal
If fault remains
(23)Perform inverter discharging work, then replace right

2-47
Logic
BG 0 to 5V V
224
L
3 Inside Inside
6 212 229 4 of of
O cover case
14
O
15
5 WG 254 12V R 16 P Fuse
R 252 14V RP
Power 3 R 253 8V RL
17
N Battery (-)
4 18 DSP IMS
6 U IUR
1
Power card V IVR
2 Flat
CN4
5 cable W IWR
6
7
19

DSP flat
127 Speed
cable sensor W TWR
Inverter 146
M U TUR
case 145 TVR
V
126
DSP card Thermal
124 sensor
125
211241
2-48
Problem: Traction Motor L.H. Open (46)

(1) Situation
(2) Possible cause

Faulty contact or wire breakage of left traction motor cable, faulty left traction motor, faulty contact or wire
breakage of left traction inverter connector, faulty contact of DSP flat cable in left traction inverter, wire breakage
of main harness, faulty power supply card of logic unit, faulty DSP card of left traction inverter, faulty left
traction inverter, when restarting after motor shorted.

Current does not flow when torque instruction is requested.
(4) Checks
(5) Check left traction inverter and motor for cable

looseness and improper contact.
Normal Abnormal
(6) Disconnect left traction motor cables from inverter.

(8) Check connector CN6 of right traction inverter for (9) Measure resistance between terminals of both cable
(10) Disconnect connector CN6 of left

traction inverter and remove DSP
Normal Abnormal
(12) Replace left traction motor. (13) Replace motor cables.
Gate power
supply
CAN
power again.
2-49

Normal Abnormal
If fault remains

2-50
Logic
BG 0 to 5V V 3
CAN 5 WP 211
0 to 5V
224
L 4 Inside Inside
6 212 229 of of
cover case
14
15
WG 254 12V 259 RY
5 16 P Fuse
R 14V 260 RGr 17
4 253 DSP IMS
6 20 card U IUL
1
Power card V IVL
2
CN4 Flat
5 cable W IWL
6
7
19

DSP flat
132 Speed
cable sensor W TWL
Inverter 148
M U TUL
case 147
V TVL
131 Thermal
DSP card 129 sensor
130
211242
2-51
Problem: Pump Motor Open (47)

(1) Situation
(2) Possible cause

Faulty contact or wire breakage of pump motor cable, faulty pump motor, faulty contact or wire breakage of
pump inverter connector, faulty contact of DSP flat cable in pump inverter, wire breakage of main harness,
faulty power supply card of logic unit, faulty DSP card of pump inverter, faulty pump inverter, when restarting
after motor shorted.

Current does not flow when rotational speed instruction is requested.
(4) Checks
(5) Check pump inverter and motor for cable looseness

and improper contact.
Normal Abnormal
(6) Disconnect pump motor cables from inverter.

(8) Check connector CN5 of pump inverter for (9) Measure resistance between terminals of both cable
(10) Disconnect connector CN5 of

pump inverter and remove DSP
Normal Abnormal (12) Replace pump motor. (13) Replace motor cables.
Gate power
supply
CAN
power again.
2-52

Normal Abnormal
If fault remains

2-53
Logic
BG 0 to 5V V
234
L
6 212 239 4 of of
O cover case F
14
O Fuse
15
5 WG 254 12V 265
RG 16 P
R 14V RY
Power 3 R 252 8V
266
RW
17
N Battery (-)
4 253 267 18 DSP IMS
6 U IU
1
Power card V IV
2 Flat
CN4
5 cable W IW
6
7
19
CN20 Pump motor

DSP flat 138 Speed
cable sensor W PW
Inverter
137
M U PU
136 PV
case V
133 Thermal
DSP card 134 sensor
135
211243
2-54
Problem: Steering Sensor Fault (50)

(1) Situation
(2) Possible cause
Faulty steering sensor, faulty main harness, faulty logic unit.

All signal is zero. (longer 200 mS)
(4) Checks
Power supply
(5) Disconnect connectors CN4 of logic unit and CN28 of steering sensor.
Check continuity between CN4-13(4) and CN28(112).
Signal cable

Without With service tool
service tool
(8) Replace steering sensor. (9) Connect connectors CN1 and CN4.
Short-circuit CN28(114) and CN28(113).
Turn on power and check "Steer angle sw."
If fault remains of service tool input/output monitor.
(10)Disconnect battery plug. Reinstall steering sensor and 0001 [bin] Abnormal
replace logic card of logic unit.
(11) Turn off power. Open CN28(114) and
CN28(113). Short-circuit CN28(115) and
CN28(113). Turn on power and check
"Steer angle sw." of service tool input/
output monitor.
0010 [bin] Abnormal
(12) Turn off power. Open CN28(115) and CN28(113).

Turn on power and check "Steer angle sw." of
service tool input/output monitor.
0100 [bin] Abnormal
(13) Turn off power. Open CN28(116) and CN28(113).

Turn on power and check "Steer angle sw." of
service tool input/output monitor.
1000 [bin] Abnormal
2-55
(14) (15) Disconnect battery plug.

Disconnect battery plug. Replace logic card of
Replace steering sensor. logic unit.
2-56
Power card
CN28
CN4
R Battery voltage 112 113
13 4
B 21 114 117
15
GND 115 116
Logic CN28
CN1 112
R
sig 1 53 G 114
G
sig 2 54 W 115
W
Y Y
sig 3 55 116
L L
sig 4 56 117
113 B Steering
sensor
Angle sig 4 sig 3 sig 2 sig 1

Left 0 1 0 0 "0": 12 V
0 1 0 1 "1": 0 V
0 1 1 1
0 1 0
Sensor type is
1
0
open collector.
0 1 0
0 0 1 1
0 0 0 1
Center 1 0 0 0
1 0 0 1
1 0 1 1
1 0 1 0
1 1 1 0
1 1 1 1
1 1 0 1
Right 1 1 0 0
211244
2-57
Problem: Accelerator Sensor Fault (51)

(1) Situation
(2) Possible cause

Improper accelerator pedal linkage, faulty accelerator sensor, faulty main harness, faulty logic unit.

Accelerator sensor voltage is out of range of 0.2 V to 4.8 V.
Sensor voltage is 1.41 V or more when accelerator switch is opened.
Sensor voltage is 0.3 V or less when accelerator switch is closed.
(4) Checks
Raise front wheels until they clear floor.
Without service tool With service tool
(6) Check accelerator sensor voltage with input/output

(5) Disconnect battery plug. monitor and confirm value is in range of 0.2V to 4.8V.
Check relation between sensor voltage and accelerator
switch operation.
0.3V or less: OFF
(7) Check link length of accelerator pedal. 1.41V or more: ON
Abnormal signal Interrupted
Normal Abnormal
(9) Disconnect battery plug. (10) Adjust accelerator

(8) Adjust accelerator pedal
pedal linkage.
linkage.

Disconnect connector CN16 of accelerator sensor.
(13) Check continuity between CN3-20 and CN16(142).

(Sensor voltage)

(Switch)


With service tool
Without
service tool
2-58
Without With service tool

service tool
(17) Replace accelerator pedal. (18)Connect connector CN2 and CN3. Turn on power and
check voltage between CN16(141) and CN16(140).
If fault remains 5V Not 5 V

(20) Turn off power. Short-circuit CN16(141)
and CN16(142). Turn on power and check
accelerator voltage with service tool.
(21) Reinstall accelerator pedal, then replace logic card 5V Not 5 V
of logic unit. See page 1-47.
(22) Turn off power. Open CN16(141) and
CN16(142). Short-circuit CN16(142) and
CN16(143). Turn on power and check
accelerator voltage with service tool.
0V Not 0 V
(23) Replace accelerator (24) Disconnect battery

pedal. plug.
(25) Replace logic card of

logic unit.
2-59
CN16
Logic
CN2 143 144 142 141
L 12V/0V
SW 42 144
Accelerator
CN16
L
RW 5V R
24 141
AN 20 G 0.30 to 1.40V
142
G
L 140 GND B
23 143
Logic
CN3
211245
2-60
Problem: Traction Motor R.H. Pulse Input Fault (52)

(1) Situation
(2) Possible cause

Faulty contact of right traction inverter connector, faulty connection of right traction motor connector and cable,
faulty 12V input voltage of right traction inverter, faulty contact or wire breakage of right traction motor speed
sensor harness, faulty DSP card of right traction inverter, faulty right traction motor speed sensor.

Motor rotation speed is more than 5800 rpm.
(4) Checks
(5) Check to see if right traction motor cables (U, V and W-

phases) are connected to right traction inverter properly.
Normal Abnormal
(6) Check to see if connector CN7 of right traction

(7) Connect cables properly.
inverter is fastened securely.
Normal Abnormal
(8) Check to see if connector CN14 of right traction

(9) Fasten connector securely.
motor speed sensor is fastened securely.
Normal Abnormal
Sensor
Power
supply
CAN
power again.
2-61

Normal Abnormal
(18) Replace DSP card of right traction inverter. See page 1-44. (19) Replace power supply card of logic unit. See page 1-48.
If fault remains

right traction motor. (DSP card is normal.)
See page 3-4.
2-62
Logic
BG 0 to 5V V
224
L
3 Inside Inside
6 212 229 4 of of
O cover case
14
O
15
5 WG 254 12V R 16 P Fuse
R 252 14V RP
Power 3 R 253 8V RL
17
N Battery (-)
4 18 DSP IMS
6 U IUR
1
Power card V IVR
2 Flat
CN4 12V Y
5 cable W IWR
0 to 5V Y
6
0 to 5V B
7
GND O 19

O 127 Speed
B sensor W TWR
Y
146
M U TUR
145 TVR
Y V
126
Thermal
124 sensor
125
211246
2-63
Problem: Traction Motor L.H. Pulse Input Fault (53)

(2) Possible cause

Faulty contact of left traction inverter connector, faulty connection of left traction motor connector and cable,
faulty 12V input voltage of left traction inverter, faulty contact or wire breakage of left traction motor speed
sensor harness, faulty DSP card of left traction inverter, faulty left traction motor speed sensor.

(4) Checks
(5) Check to see if left traction motor cables (U, V and W-

phases) are connected to left traction inverter properly.
Normal Abnormal
(6) Check to see if connector CN6 of left traction inverter

is fastened securely.
Normal Abnormal
(8) Check to see if connector CN15 of left traction motor

speed sensor is fastened securely.
Normal Abnormal
Sensor
Power
supply
CAN

power again.
2-64

Normal Abnormal
If fault remains

traction motor. (DSP card is normal.) See page 3-4.
2-65
Logic
BG 0 to 5V V 3
224
L 4 Inside Inside
6 212 229 of of
cover case
14
15
WG 254 12V 259 RY 16
5 P Fuse
R 14V 260 RGr 17
Power 3 252
R 253 8V 261 R 18 DSP N Battery (-)
4 IMS
6 20 card U IUL
1
Power card V IVL
2
CN4 12V V 5 Flat
cable W IWL
0 to 5V L 6
0 to 5V G
7
GND O 19

O 132 Speed
G sensor W TWL
L
148
M U TUL
147 TVL
V
V 131 Thermal
129 sensor
130
211247
2-66
Problem: FC Control Lever Fault (54)

(1) Situation
Display: "54". Related lever operation inhibited. Normal traction motor and power steering operations.
(2) Possible cause

Faulty lift FC control lever, faulty tilt FC control lever, faulty attachment 1 and 2 FC control levers, faulty main harness,
faulty input unit.

FC control lever voltage is out of range of 0.1 V to 4.9 V.
(4) Checks
Operate all FC control levers to find faulty FC control lever.
Attachment 2: 4-valve specification only
Attachment 1 and 2: Inspect by checking pump motor running sound if attachment is not installed.
Found Not found, with service tool
(5) Find faulty FC control lever with FC input/output
monitor. FC control lever voltage should be 2.5V±0.2V
if it is not operated.
Notice: -100 % equal 0.25 V

(6) Turn off power. Replace abnormal FC control lever with normal 0 % equal 2.5 V
control lever. Turn on power. Check faulty FC control lever. 100 % equal 4.75 V
Not changed Changed

Replace FC control lever.

(9) Disconnect connector CN2 of input unit. Disconnect connectors CN3 to CN6 of FC control levers. (FC-IN harness)
Lift Tilt Attachment 1 Attachment 2
(10) (11) (12) (13)

Check continuity between Check continuity between Check continuity between Check continuity between
CN2-25 and CN3(7), CN2-27 and CN4(9), CN2-29 and CN5(11), CN2-31 and CN6(13),
CN2-23 and CN3(5) and CN2-23(5) and CN4(15) and CN2-23(5) and CN5(17) and CN2-23(5) and CN6(19) and
CN2-24 and CN3(6). CN2-24(6) and CN4(16). CN2-24(6) and CN5(18). CN2-24(6) and CN6(20).
Continuity No continuity Continuity No continuity Continuity No continuity Continuity No continuity
(14) Replace input unit. See page 1-49. (15) Repair or replace harness. (FC-IN harness)
If fault remains
discharging work.
(17) Reinstall input unit and replace harness.

(FC-IN harness)
2-67
FC-IN harness FC control lever

CN2 R CN3
5 CN3
R 5V Y
23 5
G Lift 5 8 7 6
Input Y 0 to 5V
25 7 6 B
unit
G 0 to 5V R CN4 CN4
26 8 15
CN2 Y Y
0 to 5V Tilt 15 10 9 16
27 9 L
31 1 L
28 10
0 to 5V
16
B
32 2
Y 0 to 5V R CN5 CN5
29 11 17
Y Attachment 1 17 12 11 18
Br 0 to 5V Br
30 12
B
31 Y 13
0 to 5V 18
R CN6 CN6
W 0 to 5V 19
32 14 Y Attachment 2 19 14 13 20
W
24 B
GND
6
20
B
211248
2-68
Problem: FC Solenoid Fault (55)

(1) Situation
Display: "55". Related lever operation inhibited. Normal traction motor and power steering operations.
(2) Possible cause

Faulty lift solenoid, faulty tilt solenoid, faulty attachment 1 and 2 solenoids, faulty main harness, faulty output unit.

When signal is outputted, current is out of range of 0.16 A to 1.9 A.
(4) Checks
Operate all FC control levers to find faulty solenoid.
Attachment 2: 4-valve specification only
Attachment 1 and 2: Inspect by checking pump motor running sound if attachment is not installed.
Found Not found, with service tool
(5)Find faulty solenoid with FC input/output monitor.

Solenoid current should flow when FC control lever is
operated.

(7) Disconnect connector CN9 of output unit. Disconnect connectors CN1 to CN8 of solenoids. (FC-OUT harness)
Lift Tilt Attachment 1 Attachment 2
(8) Check continuity between (9) Check continuity between (10) Check continuity between (11) Check continuity between
CN9-2 and CN2(2) and CN9-5 and CN4(5) and CN9-8 and CN6(8) and CN9-11 and CN8(11) and
CN9-3(3) and CN2(13). CN9-6(6) and CN4(14). CN9-9(9) and CN6(15). CN9-12(12) and CN8(16).
Continuity No continuity Continuity No continuity Continuity No continuity Continuity No continuity
(12) Measure resistance of solenoid coil. [6.6 Ω at -30 °C(-22 °F) (13) Repair or replace harness. (FC-OUT harness)
to 9.8 Ω at 80 °C (176 °F)]
Normal Abnormal
(14) Replace related solenoid.

(15) Check short circuit between CN9-1(1), CN9-2(2) and CN9-3(3).
Check short circuit between CN9-4(4), CN9-5(5) and CN9-6(6).
Check short circuit between CN9-7(7), CN9-8(8) and CN9-9(9).
Check short circuit between CN9-10(10), CN9-11(11) and
CN9-12(12).
Not shorted Shorted
(16) Replace output unit. See page 1-50. (17) Repair or replace harness. (FC-OUT harness)
2-69
31 32 30 28 29 27 25 26 24 22 23 21 (Output unit side)
11 12 10 8 9 7 5 6 4 2 3 1 Output unit
W O Y O B G G Y V W G L CN9
FC-OUT harness
16 11 12 10 15 8 9 7 14 5 6 4 13 2 3 1
ATT2B ATT2A ATT1B ATT1A TILTB TILTA LIFTB LIFTA

CN8 CN7 CN6 CN5 CN4 CN3 CN2 CN1
Solenoid coils
211249
2-70
Problem: FC Solenoid Current Leak (56)

(1) Situation
Display: "56". All truck operations inhibited. Line contactor OPEN and pump contactor OPEN.
(2) Possible cause

Faulty lift solenoid, faulty tilt solenoid, faulty attachment 1 and 2 solenoids, faulty main harness, faulty output
unit.

When signal is not outputted, current is more than 0.18 A.
(4) Checks
Disconnect battery plug, then perform inverter
(5) Disconnect connector CN9 of output unit. Disconnect

connectors CN1 to CN8 of solenoids.
(6) Check short circuit between all pin patterns.

[CN9-1(1) to CN9-12(12)]
Not shorted Shorted
(7) Measure solenoid coil resistance.

[6.6Ω at -30 °C(-22 °F) to 9.8Ω at 80 °C(176 °F)]
Normal Abnormal
(9) Replace output unit. See page 1-50. (10) Replace related solenoid.
2-71
31 32 30 28 29 27 25 26 24 22 23 21 (Output unit side)
11 12 10 8 9 7 5 6 4 2 3 1 Output unit
W O Y O B G G Y V W G L CN9
FC-OUT harness
16 11 12 10 15 8 9 7 14 5 6 4 13 2 3 1
ATT2B ATT2A ATT1B ATT1A TILTB TILTA LIFTB LIFTA

CN8 CN7 CN6 CN5 CN4 CN3 CN2 CN1
Solenoid coils
211249
2-72
Problem: Pump Motor Pulse Input Fault (57)

(1) Situation
(2) Possible cause

Faulty contact of pump inverter connector, faulty connection of pump motor connector and cable,
faulty 12V input voltage of pump inverter, faulty contact or wire breakage of pump motor speed sensor harness,
faulty DSP card of pump inverter, faulty pump motor speed sensor.

Motor rotation speed is zero while current flows to motor.
Motor rotates in reverse.
(4) Checks
(5) Check to see if pump motor cables (U, V and W-phases)

are connected to pump inverter properly.
Normal Abnormal
(6) Check to see if connector CN5 of pump inverter is

fastened securely.
Normal Abnormal
(8) Check to see if connector CN20 of pump motor

speed sensor is fastened securely.
Normal Abnormal
Sensor
Power
supply
CAN
power again.
2-73

Normal Abnormal
If fault remains

pump motor. (DSP card is normal.) See page 3-4.
2-74
Logic
BG 0 to 5V V
CAN 5 WP 211
0 to 5V
234
L
6 212 239 4 of of
O cover case F
14
O Fuse
15
5 WG 254 12V 265
RG 16 P
R 252 14V RY
Power 3 R 8V
266
RW
17
N Battery (-)
4 253 267 18 DSP IMS
6 U IU
1
Power card V IV
2 Flat
CN4 12V L
5 cable W IW
0 to 5V R 6
0 to 5V Y
7
GND V 19
CN20 Pump motor

V 138 Speed
Y sensor W PW
R
137
M U PU
136 PV
L V
133 Thermal
134 sensor
135
211250
2-75
Problem: Display Communication Fault (60)

(1) Situation
Display: "60". Normal truck operation.
(2) Possible cause

Faulty main harness, faulty display unit, faulty logic unit.

Communication is impossible.
Hour meter data of display unit is abnormal.
(4) Checks
(5) Disconnect connector CN3 of controller. Disconnect

connector CN8 of display unit.
(6) Check to see if these are shorted to other signal cables. (7) Repair or replace harness.
Not shorted Shorted
(8) Replace display unit. (9) Repair or replace harness.
If fault remains

(11) Replace logic card of logic unit. See page 1-47.
2-76
CN9 Key switch

R
Power card 4
G
CN4 13
Battery +
R CN18
13 4 G
2 10 A
G
Fuse holder
CN8
Logic CN8
CN3 152 149
Battery voltage
151 R
151150
WB 149 0 to 12V G
TXD 14
Display
L 0 to 12V L
RXD 16 150
GND 23 L 140
GND
152 B
211251
2-77
Problem: Logic Card Initialize Failure (61)

(1) Situation
(2) Possible cause

Setup Option Group 3 data not set, Setup Option Group 1 and 2 default data not set, faulty Setup Option data,
faulty logic unit.

Setup Option data is in abnormal setting range.
MC specification is set at #43 while CAN data is received from input unit or output unit.
Other model is set at #40 while steering sensor is installed.
(4) Checks
Turn off power, then turn on power in Setup Option Group 3 setting. See page 1-16.
(5) Set Setup Option Group 3 data. See page 1-28 to 1-30.
(6) Set Setup Option default data. See page 1-16.
(7) Turn on power in "RUN" mode. See page 1-16.
If fault remains
(8) With service tool, set Setup Option Group 3 data.
(9) With service tool, set Setup Option default data.
If fault remains
(13) With service tool, set Setup Option default data.
2-78
Problem: Logics Fault (62)

(1) Situation
(2) Possible cause

Faulty EEPROM data, faulty logic unit.

ROM/RAM SUM value of logic card is different from check data.
EEPROM SUM value of logic card is different from check data.
(4) Checks
Turn off power, then turn on power in Setup Option Group 3 setting. See page 1-16.
(5) Set Setup Option Group 3 data.
(6) Set Setup Option default data.
(7) Turn on power in "RUN" mode. See page 1-16.

Error code "61"
If fault remains "62"
(8) Disconnect battery plug, then perform inverter (9) See troubleshooting for code "61". See page 2-78.

Set Setup Option default data.
2-79
Problem: Traction Inverter R.H. Fault (63)

(1) Situation
(2) Possible cause

Faulty contact or wire breakage of DSP flat cable in right traction inverter, faulty DSP card of right traction inverter,
faulty right traction inverter, faulty main harness, faulty logic unit.

Right traction inverter is connected as pump inverter (CN7-9 is connected to GND).
ROM/RAM SUM value of right taction inverter is different from check data.
Communication with right traction inverter is impossible.
(4) Checks

Normal Abnormal
8V power
supply
(6) Check continuity between CN4-4 and CN7-18(253). (7) Refasten flat cable or replace inverter. See page 1-42.
CAN
Mode
(9) Check CN7-8 and CN7-9 that pin is not inserted in.
Normal Abnormal
power again.

Normal Abnormal
(14) Replace DSP card of right traction inverter. (15) Replace power supply card of logic unit.
See page 1-44. See page 1-48.
2-80
Logic
BG 0 to 5V V
224
L
3 Inside Inside
6 212 229 4 of of
O cover case
14
O
15
5 WG 254 12V R 16 P Fuse
R 252 14V RP
Power 3 R 253 8V RL
17
N Battery (-)
4 18 DSP IMS
6 U
mode 1 8
Power card V
mode 2 9 Flat
CN4
cable W
DSP flat
cable
Inverter
case
DSP card
211252
2-81
Problem: Traction Inverter L.H. Fault (64)

(1) Situation
(2) Possible cause

Faulty contact or wire breakage of DSP flat cable in left traction inverter, faulty DSP card of left traction inverter,
faulty left traction inverter, faulty main harness, faulty logic unit.

Left traction inverter is connected as pump inverter (CN6-9 is connected to GND).
ROM/RAM SUM value of left traction inverter is different from check data.
Communication with left traction inverter is impossible.
(4) Checks

or wire breakage.
Normal Abnormal
8V power
supply
(6) Check continuity between CN4-4(253) and CN6-18(261). (7) Refasten flat cable or replace inverter. See page 1-42.
CAN
Mode
(10) Check CN6-9 that pin is not inserted in.

Normal Abnormal
power again.

Normal Abnormal
(15) Replace DSP card of left traction inverter. (16) Replace power supply card of logic unit.
2-82
Logic
BG 0 to 5V V 3
224
L 4 Inside Inside
6 212 229 of of
cover case
14
15
WG 254 12V 259 RY
5 16 P Fuse
R 14V 260 RGr 17
Power 3 252
R 253 8V 261 R 18 N Battery (-)
4 DSP IMS
6 20 card U
B
mode 1 8
Power card 262 V
mode 2 9 Flat
CN4
cable W
GND
DSP flat
cable
Inverter
case
DSP card
211253
2-83
Problem: Pump Inverter Fault (65)

(1) Situation
(2) Possible cause

Faulty contact or wire breakage of DSP flat cable in pump inverter, faulty DSP card of pump inverter,
faulty pump inverter, faulty main harness, faulty logic unit.

Pump inverter is connected as traction inverter (CN6-9 is opened).
ROM/RAM SUM value of pump inverter is different from check data.
Communication with pump inverter is impossible.
(4) Checks

or wire breakage.
Normal Abnormal
8V power
supply
(6) Check continuity between CN4-4(253) and CN5-18(267). (7) Refasten flat cable or replace inverter. See page 1-42.
CAN
Mode
(10) Check CN5-8 that pin is not inserted in.

Normal Abnormal
power again.

Normal Abnormal
(15) Replace DSP card of pump inverter. (16) Replace power supply card of logic unit.
2-84
Logic
BG 0 to 5V V
CAN 5 WP 211
0 to 5V
234
L
6 212 239 4 of of
O cover case F
14
O Fuse
15
5 WG 254 12V 265
RG
16 P
R 14V RY
Power 3 R 252 8V
266 17
RW N Battery (-)
4 253 267 18 DSP IMS
B 255 GND 268 B20 card card
6 U
mode 1 8
Power card mode 2 B V
9 Flat
CN4 263
cable W
GND
DSP flat
cable
Inverter
case
DSP card
211254
2-85
Problem: Input Unit Fault (67)

(1) Situation
(2) Possible cause

Faulty remote input unit, faulty main harness, faulty logic unit.

ROM/RAM SUM value of input unit is different from check data.
Communication with input unit is impossible.
(4) Checks
(5) Check input unit status with FC input/output

monitor.
Normal Error
(7) Disconnect battery plug, then replace input unit.

(6) Turn off power.
See page 1-49.
(8) Disconnect connector CN2 of input unit, then measure

voltage between CN2-1(1) and CN2-2(2).
Confirm value is 14V±2V.
Normal Abnormal
(9) Turn off power, then disconnect connector CN23 of

harness B and connector CN1 of FC-IN harness.
(10) Measure voltage between CN23(278) and CN23(279).

Confirm value is 14V±5% .
Normal Abnormal
(11) Repair or replace (12) Disconnect battery plug,

FC-IN harness. then perform inverter
discharging work.
See page 1-41.
(14) Check continuity between CN4-3(252) and CN23(278).

(13) Disconnect battery plug, then perform inverter Check continuity between CN4-6(255) and CN23(279).
discharging work. See page 1-41. Continuity No continuity
(15) Replace power supply (16) Repair or replace main

card of logic unit. harness.
See page 1-48.
2-86

(18) Replace input unit. See page 1-49. (19) Disconnect connector CN1 of FC-IN harness.
Check continuity between CN23(283) and CN3-5(211).
(20) Repair or replace (21) Repair or replace main

FC-IN harness. harness.
2-87
FC-IN Power card

CN2 harness CN1, CN23 CN4
G GND B
1 1 279 255 6
Input Y 14V R
unit 2 2 278 252 3
Br 0 to 5V
7 3 283
L 0 to 5V Logic
8 4 284
CN3
BG
211 5
CAN
21 3 1 279 283 280 WP
212 6
22 4 2 278 284 281
CN1 CN23 Harness B
211255
2-88
Problem: Output Unit Fault (68)

(1) Situation
(2) Possible cause

Emergency switch opened, faulty remote output unit, faulty main harness, faulty logic unit.

Emergency switch is detected. ROM/RAM SUM value of output unit is different from check data.
Communication with output unit is impossible.
(4) Checks
Check emergency switch.
Not pushed Pushed
(5) Release emergency switch.
(6)
(7) Check output unit status with FC input/output

monitor.
Normal Error
(9) Disconnect battery plug, then replace output unit.

(8) Turn off power. See page 1-50.
(10) Disconnect connector CN22 of output unit, then

measure voltage between CN22-20(293) and
Normal Abnormal
(11) Disconnect battery plug, then perform inverter (12) Disconnect battery plug, then perform inverter
discharging work. See page 1-41. discharging work. See page 1-41.
(13) Disconnect connector CN3 of logic unit. (14) Check continuity between CN4-3(252) and
Check continuity between CN3-5(211) and CN22-13(295). CN22-20(293).
Check continuity between CN3-6(212) and CN22-14(296). Check continuity between CN4-6(255) and
Continuity No continuity CN22-19(294).
(15) Replace power supply (16)Repair or replace main

card of logic unit. harness.
See page 1-48.
(17) Replace output unit. See page 1-50. (18) Repair or replace main harness.
2-89
Power card
CN22 CN4
B GND
19 293 252 3
Output R 14V
unit 20 294 255 6
V 0 to 5V BG
13 295 211 5
CAN
L 0 to 5V 212 WP
14 296 6
Logic
CN3
Emergency switch
G 300 O/Battery voltage
3
YB 299 YB G L
4 299 10A FUSE 281 281
280 280 W
4
R
G Key switch
13
10A FUSE
G 2 3
R Battery +
211256
2-90
Problem: Contactor Coil Fault (72)

(1) Situation
Display: "72". All truck operations inhibited. Line contactor OPEN and pump contactor OPEN.
(2) Possible cause

Faulty line contactor, faulty pump contactor, faulty main harness, faulty logic unit.

With short circuit detection signal of logic card.
(4) Checks
(5) Find faulty contactor (line contactor or pump

contactor) with input/output monitor.
(6) Disconnect battery plug, then perform (faulty unit only)

(7)Check line contactor or pump contactor.
Line contactor Pump contactor
(8) Remove coil side terminals of (14) Remove coil side

line contactor. terminals of pump contactor.
(9) Check short circuit between coil (15) Check short circuit between
terminal plus(+)(249) and minus(-) coil terminal plus(+)(250) and
(247) of harness. minus(-)(248) of harness.
Not shorted Shorted Shorted Not shorted
(10) Measure coil resistance. (16) Measure coil resistance.

[44Ω at -30 °C (-22 °F) to (11) Repair or replace main harness. [44Ω at -30 °C (-22 °F) to
66Ω at 80 °C (176 °F)] 66Ω at 80 °C (176 °F)]
Abnormal Normal Normal Abnormal
(12) Replace line contactor. (13) Replace logic card of logic unit. (17) Replace pump contactor.
See page 1-47.
2-91
Power card
27V to
R battery voltage
+
CN4 13 4 249
27V to
battery voltage
247 -
Logic
Line contactor
CN1
+
G 250
59
B
60 27V to
battery voltage
248 -
Pump contactor
211257
2-92
Problem: Hydraulic Lock Solenoid Fault (74)

(1) Situation
Display: "74". Pump motor operation inhibited. Normal traction motor operation and power steering operation.
(MC specifications only)
(2) Possible cause

Faulty unload valve, faulty lift lock valve, faulty main harness, faulty logic unit.

With short circuit detection signal of logic card.
(4) Checks
(5) Find faulty valve (unload valve or lift lock valve) with
input/output monitor.
(6) Disconnect battery plug, then perform (faulty unit only)

Unload valve Lift lock valve
(8) Disconnect connector CN1 of logic (14) Disconnect connector CN1 of logic
unit. Disconnect connector CN27 unit. Disconnect connector CN24
of unload valve. of lift lock valve.
(9) Check short circuit between CN27 (15) Check short circuit between
(317) and CN27(318). CN24(308) and CN24(309).
Not shorted Shorted Shorted Not shorted
(10) Check short circuit between (16) Check short circuit between lift
(11) Repair or replace main harness. lock valve side connectors.
unload valve side connectors.
Measure coil resistance. Measure coil resistance.
[7.5Ω at -30 °C (-22 °F) to [7.5Ω at -30 °C (-22 °F) to
12.8Ω at 80 °C (176 °F)] 12.8Ω at 80 °C (176 °F)]
Shorted Not shorted Normal Abnormal
(12) Replace unload valve. (13)Replace logic card of logic unit. (17) Replace lift lock valve.
See page 1-47.
2-93
Power card
CN4 CN27
R
13 4 318
Unload
Logic valve
317
CN1 CN27
B
64
317 318
Logic
Harness B CN24
CN1
309 Lift
57 Y
lock
58 B
308 valve
CN24
308 309
Harness B
211258
2-94
Problem: Battery Voltage Too Low (78)

(1) Situation
(2) Possible cause

Faulty or discharged battery, low voltage battery, improper battery voltage setting (Setup Option #41), improper
battery voltage adjustment setting (Setup Option #46), faulty main harness, faulty logic unit.

Corrected battery voltage is too low.
Battery voltage is corrected with #46 value.
36 V battery: less than 30 V 48 V battery: less than 42 V
(4) Checks
Disconnect battery plug.
Measure battery voltage with tester.
34 V to 55 V Abnormal
(5) Turn on power in Setup Option Group 3 setting.

See page 1-16. (6) Charge battery or replace with proper battery.
(7) Set #41 of Setup Option Group 3.

Set #46 of Setup Option Group 3. See page 1-28 to 1-30.
(8) Turn off power and turn on power again.
If fault remains

(10) Check continuity between CN3-19(269) and contactor

POS(3).
(11) Perform inverter discharging work, then replace logic (12) Repair or replace main harness.
card of logic unit. See page 1-47.
2-95
Line contactor
Logic
NEG
CN3
Battery voltage
R
19 269 3 Fuse
+
Battery
211259
2-96
Problem: Battery Voltage Too High (79)

(1) Situation
(2) Possible cause

Faulty or highly charged battery, high voltage battery, improper battery voltage setting (Setup Option #41),
improper battery voltage adjustment setting (Setup Option #46), faulty logic unit.

Corrected battery voltage is too high.
36 V battery: more than 42 V 48 V battery: more than 60 V
(4) Checks
Measure battery voltage with tester.
34V to 55 V Abnormal
(5) Turn on power in Setup Option Group 3 setting.

See page 1-16. (6) Replace with proper battery.
(7) Set #41 of Setup Option Group 3.

Set #46 of Setup Option Group 3. See page 1-28 to 1-30.
(8) Turn off power and turn on power again.
If fault remains

If fault remains
(11) Repair or replace main harness.
2-97
Line contactor
Logic
NEG
CN3
Battery voltage
R
19 269 3 Fuse
+
Battery
211259
2-98
Problem: Direction Lever or Accelerator, Faulty Setting (E)

(1) Situation
Display: "E". Traction motor operation inhibited. Normal pump motor and power steering operations.
Line contactor OPEN.
(2) Possible cause

Key switch turned on while direction lever was left either in forward or reverse position, key switch turned on
while accelerator pedal was depressed, seat switch turned off during running, faulty direction lever switch,
faulty accelerator sensor, faulty main harness, faulty logic unit.

Detects follow signal when turning on power.
Direction lever: F or R Accelerator sensor voltage: More than 0.3 V
(4) Checks
Move direction lever to neutral, and release accelerator pedal.
If fault remains
(5) Turn off power. Move direction lever to neutral, release

accelerator pedal, then turn on power again.

With service tool
(6) Check direction lever and accelerator sensor operations (7) Turn on power in diagnosis mode. Inspect direction
with input/output monitor. lever and accelerator sensor. See page 1-35.
(8) Turn off power. (faulty unit only)
Direction lever Accelerator sensor
(9) Disconnect connector CN10 of direction lever.

Turn on power. (10) Refer to error code "51". See page 2-58.
Normal (E)
(11) Replace direction lever. (12) Disconnect connectors CN2 and CN3 of logic unit.
(13) Check short circuit between CN3-25(108) and

CN2-36(104), CN3-25(108) and CN2-37(103).
Not shorted Shorted
(15) Repair or replace

main harness.
2-99
Logic
CN2
CN10
0/12V O
Forward 37 OL 103 F
Br Direction
Reverse 36 Br 104
0/12V
R lever
GND
102
G
B2
Accel L
42 144
CN10
switch
104 103
102
Main harness
0/12V
Logic Accelerator
CN3 CN16
L
GND 25 W 108
+ 5V 24 RW 141 5V R
AN 20 G 142 0 to 5V G
L 140 GND B
GND 23 143
CN16
143 144 142 141
Main harness
211260
2-100
Problem: Seat Switch, Faulty Setting For Traction ((E))

(1) Situation
Display: "E" flickering. Traction motor operation inhibited. Normal pump and power steering operations.
Line contactor OPEN.
(2) Possible cause

Operator not on seat, seat switch turned off during running, improper seat suspension adjustment,
faulty seat switch, faulty main harness, faulty logic unit.

Detects seat switch opening when turning on power or during running.
(4) Checks
If this fault occurred If this fault occurred when
during running turning on power
(5) Stop truck, then move direction lever to neutral.

Sit properly in operator's seat and release accelerator pedal.
If fault remains Normal
Fail-safe function
(6) Turn off power. Sit on seat, then turn on power again.
If fault remains
(7) Turn off power.
(8) Adjust seat suspension.

Faulty seat switch position
(10) Disconnect connector CN25, then short-circuit

between terminals (110) and (111). Turn on
power again.

(12) Replace seat switch.

Check continuity between CN25(111) and CN2-33.
(14) Replace logic card of logic unit. See page 1-47. (15) Repair or replace main harness.
2-101
Logic
CN2
0/12V G
32
0/12V YW
33
Seat belt switch CN25
G Logic
310
Y CN3
111
G GND W
110 108 25 GND
Seat switch CN25
111 110 310
Main harness
211261
2-102
Problem: Seat Switch, Faulty Setting For Hydraulic ((L))

(1) Situation
Display: "L" flickering. Pump motor and power steering operations inhibited. Pump contactor OPEN if this fault
occurs when turning on power. Pump contactor CLOSE if this fault occurs during pump operation and then OPEN
if truck stops.
(2) Possible cause

Operator not on seat, seat switch turned off during pump motor operation, improper seat suspension adjustment,
faulty seat switch, faulty main harness, faulty logic unit.

Detects seat switch opening when turning on power or during pump operation.
(4) Checks
If this fault occurred during If this fault occurred when
pump motor operation turning on power
(5) Sit on seat, then stop pump motor operation.

Fail-safe function
If fault remains
(7) Turn off power.
(8) Adjust seat suspension.

Faulty seat switch position
(10) Disconnect connector CN25, then short-circuit

between terminals (110) and (111). Turn on
power again.
(11) Disconnect battery plug, then perform inverter (12) Replace seat switch.

Check continuity between CN25(111) and CN2-33.
2-103
Logic
CN2
0/12V G
32
0/12V YW
33
Seat belt switch CN25
G Logic
310
Y CN3
111
G GND W
110 108 25 GND
Seat switch CN25
111 110 310
Main harness
211261
2-104
Problem: Lift Lever, Faulty Setting (H1)

(1) Situation
Display: "H1" flickering. Pump motor and power steering operations inhibited. Pump contactor OPEN if this fault
if truck stops.
(2) Possible cause

Key switch turned on while operating lift lever, faulty lift control lever or lift switches 1 and 2,
faulty main harness, faulty logic unit, faulty input unit.

Detects lift control lever signal of CAN when turning on power (FC specification).
Detects lift microswitch 1 or 2 when turning on power (MC specification).
(4) Checks

Fail-safe function
(6) Turn off power. Sit on seat, then turn on power again
without lift operation.
Error code 54 or 67
If fault remains "L" flickering
(8) Refer to error code "54",

(7) Turn off power.
"67" or "(L)".
FC specification
(9) Change lift control lever to other normal control lever.

MC
specification Not changed Error changed
(12) Disconnect connector CN22 of microswitch. Sit on seat, (10) Repair or replace (11) Replace lift control
then turn on power again. FC-IN harness. lever.
(13) Disconnect battery plug, then perform inverter (14) Replace lift switch 1 or 2.

Check short circuit between CN22(303) and CN22(302).
Continuity, Not shorted No continuity, Shorted
(16) Disconnect battery plug. (17) Repair or replace main harness.

2-105
FC specification
CN3 FC-IN harness CN2
5V R
5 23
Lift 7
0 to 5V Y 25 Input
0 to 5V G
control lever 8 26 unit
GND B
6 24
CN3
5 8 7 6
FC-IN harness
MC specification Logic
CN1
CN22 0/12V Y
303 52
Lift 1
0/12V
304 W 51
GND
Lift 2 302
Logic
302 304 CN22 CN3
305 303
W
306 307 108 25
Main harness
211262
2-106
Problem: Tilt Lever, Faulty Setting (H2)

(1) Situation
if truck stops.
(2) Possible cause

Key switch turned on while operating tilt lever, faulty tilt control lever or tilt switch, faulty main harness,
faulty logic unit, faulty input unit.

Detects tilt control lever signal of CAN when turning on power (FC specification).
Detects tilt microswitch when turning on power (MC specification).
(4) Checks

Fail-safe function
without tilt operation.
Error code 54 or 67
(8) Refer to error code "54",

(7) Turn off power.
"67" or "(L)".
FC specification
MC (9) Change tilt control lever to other normal control lever.

specification Not changed Error changed
(12) Disconnect connector CN22 of microswitch. Sit on seat, (10) Repair or replace (11) Replace tilt control
then turn on power again. FC-IN harness. lever.
(13) Disconnect battery plug, then perform inverter (14) Replace tilt switch.

2-107
FC specification

5V R
15 5 23
0 to 5V Y
Tilt 9 27 Input
0 to 5V L
16
GND
6
B 24
CN4
15 10 9 16
FC-IN harness
CN22 CN1
0/12V L
305 50
Tilt
GND
302
Logic
302 304 CN22 CN3
305 303 W
306 307
108 25
Main harness
211263
2-108
Problem: Attachment 1 Lever, Faulty Setting (H3)

(1) Situation
if truck stops.
(2) Possible cause

Key switch turned on while operating attachment 1 lever, faulty attachment 1 control lever or attachment 1 switch,

Detects attachment 1 control lever signal of CAN when turning on power (FC specification).
Detects attachment 1 microswitch when turning on power (MC specification).
(4) Checks If this fault occurred during If this fault occurred when

Fail-safe function
without attachment 1 operation.
Error code 54 or 67
(7) Turn off power. (8) Refer to error code "54",

"67" or "(L)".
FC specification
MC (9) Change attachment 1 control lever to other normal

specification control lever.
Not changed Error changed
(12) Disconnect connector CN22 of microswitch.
Sit on seat, then turn on power again.
(10) Repair or replace (11) Replace attachment 1
If fault remains Normal FC-IN harness. control lever.
(13) Disconnect battery plug, then perform inverter (14) Replace attachment 1 switch.

Check short circuit between CN22(306) and
CN22(302).
2-109
FC specification

5V R
17 5 23
0 to 5V Y
Attachment 1 11 29 Input
0 to 5V Br
18
GND
6
B 24
CN5
17 12 11 18
FC-IN harness
CN22 CN1
0/12V G
306 49
Aux 1
GND
302
Logic
302 304 CN22 CN3
305 303 W
306 307
108 25
Main harness
211264
2-110

(1) Situation
if truck stops.
(2) Possible cause

Key switch turned on while operating attachment 2 lever, faulty attachment 2 control lever or attachment 2 switch,

Detects attachment 2 control lever signal of CAN when turning on power (FC specification).
Detects attachment 2 microswitch when turning on power (MC specification).
(4) Checks

Fail-safe function
without attachment 2 operation.
Error code 54 or 67
(7) Turn off power. (8) Refer to error code "54",

"67" or "(L)".
FC specification
MC
specification (9) Change attachment 2 control lever to other normal
control lever.
Not changed Error changed
(12) Disconnect connector CN22 of microswitch.
Sit on seat, then turn on power again. (10) Repair or replace (11) Replace attachment 2
If fault remains Normal FC-IN harness. control lever.
(13) Disconnect battery plug, then perform inverter (14) Replace attachment 2 switch.

Check short circuit between CN22(307) and
CN22(302).
2-111
FC specification

R 5V R
19 5 23
0 to 5V Y
Attachment 2 13 31 Input
0 to 5V W
B 20
GND
6
B 24
CN6
19 14 13 20
FC-IN harness
CN22 CN1
0/12V R
307 48
Aux 2
GND
302
Logic
302 304 CN22 CN3
305 303 W
306 307
108 25
Main harness
211265
2-112

(1) Situation
if truck stops.
(2) Possible cause

Faulty logic unit.

Detects attachment 3 signal when turning on power (MC specification).
(4) Checks

Fail-safe function
If fault remains
(7) Check to see if dust is accumulated on terminal CN1-47.
Normal Abnormal
(8) Clean terminal.

If fault remains
2-113
Logic
CN1
47 Attachment 3
switch
Logic
CN3
25 GND
211266
2-114
Problem: Battery Consumption Too Much ((Lo))

(1) Situation
Display: "Lo" flickering. Battery low indicator ON. All truck operations inhibited.
(2) Possible cause

Extremely consumed battery, faulty main harness, faulty logic unit.

Corrected battery voltage is less than 22 V.
(4) Checks
(5) Check battery voltage.

22V or more Less than 22V
(6) Set #46 of Setup Option Group 3. See page 1-30. (7) Charge battery or replace with new battery.
If fault remains

POS(3).
2-115
Line contactor
Logic
NEG
CN3
Battery voltage
R
19 269 3 Fuse
+
Battery
211259
2-116
Problem: Battery Consumption Much

(1) Situation
Battery low indicator flickers. Traction motor operation restricted to "ECONOMY" mode. Normal pump motor
and power steering operations.
(2) Possible cause

Consumed battery, improper battery voltage adjustment setting (Setup Option #46), faulty main harness,
faulty logic unit.

Corrected battery voltage is less than 25 V.
(4) Checks
(5) Check battery voltage.

25V or more Less than 25V
(6) Set #46 of Setup Option Group 3. See page 1-30. (7) Charge battery or replace with new battery.
If fault remains

POS(3).
2-117
Line contactor
Logic
NEG
CN3
Battery voltage
R
19 269 3 Fuse
+
Battery
211259
2-118
Locations of Major Components and Connectors
NOTE
1. The figures described below contain the major components and connectors based on the actual FC model.
2. The component names are basically quoted from the Electrical Schematic and some of the names may be
different from the text the Electrical Diagram.
Joystick box, input unit, output unit, logics and connectors
Seat assy
Joystick box
Input unit
Output unit CN22
Output harness Logics GSE CN21 CN23

Logics power CN4
Seat harness
FC control valve
Logics
DRS switch CN17
211289
2-119
Display, FNR lever assembly, PDS relay, PDS buzzer and connectors
Head lamp (R)
Head lamp (L)
Display
FNR lever assy
CN10
CN8
Horn
PDS relay
PDS buzzer
CN15
CN14
211290
Accelerator, foot brake switch, park brake switch, brake fluid sensor and connectors
Horn SW
Park brake SW
CN11
Accelerator CN16
Brake fluid sensor
Foot brake SW
211291
2-120
Motors, inverters, contactor panel assembly and battery cable
Traction motor R Traction inverter (L)
Traction inverter (R)
Battery cable
Inverter pump
Contactor panel assy
Traction motor L
Pump motor 211288
Wheel angle sensor, backup buzzer, working lamp and connectors
Working lamp
Backup buzzer (OP)
Inverter pump CN5
Inverter trac (L) CN6
Inverter trac (R) CN7
Wheel angle sensor
CN28
CN20
211292
2-121

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TROUBLESHOOTING FOR CONTROL CIRCUITS

Before replacing devices

Disconnect battery plug and discharge the inverters before

Disconnect connector CN4 of logic unit. Check continuity between

Normal Repair or replace harness.

Connection of the service tool Error code display

How to clean harness connectors and system

2. After checking the connector for continuity, wash it as

Contact surface Three Bond 2501S

Problem: Traction Motor R.H., Overheating (E0)

(2) Possible cause

(3) How the error code is triggered.

(5) Traction motor becomes normal.

(7) Adjust brake.

(8) Lift front wheels, and disengage parking brake.

(9) Check if truck is operated on steep

(10) Perform inverter discharging work. See page 1-41.

(11) Replace right traction (12) Replace right traction

(13) Confirm temperature of right traction motor with

(18) Disconnect connector CN14 of right traction motor

(25) Measure voltage between CN7-17(252) and

(26) Disconnect battery plug.

(27)Replace power supply card of logic unit. See page 1-48.

(29) Disconnect battery (30)Disconnect battery plug.

(31)Replace DSP card of right traction inverter. See page 1-44.

CN14 Traction motor (right)

Problem: Traction Motor L.H., Overheating (E1)

(2) Possible cause

(3) How the error code is triggered.

(5) Traction motor becomes normal.

(7) Adjust brake.

(8) Lift front wheels, and disengage parking brake.

(10) Perform inverter discharging work. See page 1-41.

(11) Replace left traction (12) Replace left traction

(13) Confirm temperature of left traction motor with

(18) Disconnect connector CN15 of left traction motor

(25) Measure voltage between CN6-17(260) and

(26) Disconnect battery plug.

(28) Ensure all connectors are connected. Check Run

(29) Disconnect battery (30) Disconnect battery plug.

CN15 Traction motor (left)

*1: With connector disconnected

Problem: Pump Motor, Overheating (E2)

(2) Possible cause

(3) How the error code is triggered.

(5) Pump motor becomes normal.

(6) Check if truck is operated to lift large cargo load.

(7) Perform inverter discharging work. See page 1-41.

(8) Check oil pressure of gear pump and hydraulic lines.

(9) Replace pump motor. (10)Repair or replace gear

(11) Confirm temperature of pump motor with

(16) Disconnect connector CN20 of pump motor

(23) Measure voltage between CN5-17(266) and

(24)Disconnect battery plug.

(27) Disconnect battery (28) Disconnect battery

CN20 Pump motor

Problem: Traction Inverter R.H., Overheating (E5)

(2) Possible cause