U341e PDF
U341e PDF
U341e PDF
1. General
The compact and high-capacity 4-speed U341E automatic transaxle [Super ECT (Electronic Controlled
Transaxle)] is used.
The following chart describes the changes from the previous model.
Specification
CH
Model New Previous
Transaxle U341E A246E
Engine 1ZZ-FE 1ZZ-FE
1st 2.847 4.005
2nd 1.552 2.208
Gear Ratio*1 3rd 1.000 1.425
4th 0.700 0.981
Reverse 2.343 3.272
Differential Gear Ratio 4.237 2.962
Fluid Capacity*2 Liters (US qts, Imp.qts) 6.9 (7.3, 6.1) 7.6 (8.0, 6.7)
Fluid Type ATF Type T-IV ATF Type D-II
Weight (Reference)*3 kg (lb) 70 (31.8) 80.2 (36.4)
*1: Counter Gear Ratio Included
*2: Differential Included
*3: Weight shows the figure with the fluid fully filled
CH-38 CHASSIS – AUTOMATIC TRANSAXLE
F1
C3
B1 B2
Specification
C1 Forward Clutch 4
C2 Direct Clutch 3
C3 Reverse Clutch 3
The No
No. of Discs
B1 OD & 2nd Brake 2
B2 2nd Brake 4
B3 1st & Reverse Brake 4
F1 No.1 One-Way Clutch The No. of Sprags 16
F2 No.2 One-Way Clutch The No. of Rollers 15
The No. of Sun Gear Teeth 46
Front Planetary Gear The No. of Pinion Gear Teeth 21
The No. of Ring Gear Teeth 85
The No. of Sun Gear Teeth 32
Rear Planetary Gear The No. of Pinion Gear Teeth 21
The No. of Ring Gear Teeth 75
The No. of Drive Gear Teeth 52
Counter Gear
The No. of Driven Gear Teeth 53
CHASSIS – AUTOMATIC TRANSAXLE CH-39
2. Torque Converter
This torque converter has optimally designed fluid passages and impeller configuration resulting in
substantially enhanced transmission efficiency to ensure better starting, acceleration and fuel economy.
Furthermore, a hydraulically operated lock-up mechanism which cuts power transmission losses due to
slippage at medium and high speeds is used.
Specification
Pump Turbine Runner
3-Element, 1-Step,
p 2-Phase Impeller
Torque Converter Type
(with Lock-up Mechanism)
Stall Torque Ratio 1.8 Lock-up
Stator Clutch
OD Input
Shaft
CH
One-way
Clutch
240CH102
3. Oil Pump
The shape of the teeth in the oil pump have been changed and the crescent has been discontinued, has been
adopted.
As a result, the oil pump has been made more compact, and the driving torque has been reduced, thus attaining
excellent volumetric efficiency during low-speed operation.
Crescent
U341E Conventional
165CH10
CH-40 CHASSIS – AUTOMATIC TRANSAXLE
Construction
A CR-CR type planetary gear has been adopted in the planetary gear unit, which is located on the input
shaft. This planetary gear is a type of planetary gear unit that joins the front and rear planetary carriers
to the ring gear. As a result, the unit has been made significantly more simple and compact.
A centrifugal fluid pressure canceling mechanism has been adopted in the C1 clutch, which is applied
when the gears are shifted from 3rd to 4th.
F2 B3
Front Planetary Gear
Rear Planetary Gear
Counter Drive Gear
C1
C2
Intermediate Shaft
C3 F1
216CH07
Function of Component
Component Function
C1 Forward Clutch Connect input shaft and front planetary sun gear.
C2 Direct Clutch Connect intermediate shaft and rear planetary carrier.
C3 Reverse Clutch Connect intermediate shaft and rear planetary sun gear.
B1 OD & 2nd Brake Lock the rear planetary sun gear.
B2 2nd Brake Prevents rear planetary sun gear from turning counterclockwise.
B3 1st & Reverse Brake Lock the front planetary ring gear and rear planetary carrier.
F1 No.1 One-Way Clutch Prevents rear planetary sun gear from turning counterclockwise.
Prevents front planetary ring gear and rear planetary carrier from turning
F2 No.2 One-Way Clutch
counterclockwise.
These gears change the route through which driving force is transmitted, in
Planetary Gears accordance with the operation of each clutch and brake, in order to increase
or reduce the input and output speed.
CHASSIS – AUTOMATIC TRANSAXLE CH-41
C1
C2
Intermediate Shaft
C3 F1
193CH39
CH-42 CHASSIS – AUTOMATIC TRANSAXLE
F2
Rear Planetary Gear B3 Front Planetary Gear
Counter Drive Gear
C1
C2
Intermediate Shaft
C3 F1
193CH40
F2
Rear Planetary Gear B3 Front Planetary Gear
Counter Drive Gear
C1
C2
Intermediate Shaft
C3 F1
193CH41
C1
C2
Intermediate Shaft
C3 F1
171CH08
CHASSIS – AUTOMATIC TRANSAXLE CH-43
F2
B3 Front Planetary Gear
Rear Planetary Gear
Counter Drive Gear
C1
C2
Intermediate Shaft
C3 F1
193CH42
CH
1st Gear (S mode 1 Position)
F2
B3 Front Planetary Gear
Rear Planetary Gear
Counter Drive Gear
C1
C2
Intermediate Shaft
C3 F1
193CH43
F2
B3 Front Planetary Gear
Rear Planetary Gear
Counter Drive Gear
C1
C2
Intermediate Shaft
C3 F1
193CH44
CH-44 CHASSIS – AUTOMATIC TRANSAXLE
Chamber A
C1 Clutch
Chamber B
240CH88
By utilizing the lubrication fluid such as that of the shaft, the same amount of centrifugal force is applied,
thus canceling the centrifugal force that is applied to the piston itself. Accordingly, it is not necessary to
discharge the fluid through the use of a check ball, and a highly responsive and smooth shifting
characteristic has been achieved.
Clutch
Centrifugal Fluid Pressure
Applied to the Chamber A
General
The valve body consists of the upper and lower valve bodies and 6 solenoid valves.
The 6 solenoid valves are installed in the lower valve body for serviceability.
Solenoid Valve SL
Solenoid Valve S2
Solenoid Valve S1 Solenoid Valve SLT
Solenoid Valve SB Solenoid Valve ST
240CH21
240CH103
CH-46 CHASSIS – AUTOMATIC TRANSAXLE
Accumulator
Control Valve
240CH22
4-3 Shift Timing
Lock-Up Control Valve
Valve No.2
General
The electronic control system of the U341E automatic transaxle consists of the controls listed below.
System Function
The solenoid valve SLT minutely controls the clutch pressure in accordance
Clutch Pressure Control
with the engine output and driving conditions.
Actuates the solenoid valve SLT to control the line pressure in accordance
Line Pressure Control with information from the engine & ECT ECU and the operating conditions
of the transaxle.
Retards the engine ignition timing temporarily to improve shift feeling
Engine Torque Control
during up or down shifting .
Controls to restrict the 4th upshift or to provide appropriate engine braking
Shift Control in Uphill Traveling by using the engine & ECT ECU to determine whether the vehicle is traveling
uphill. CH
The engine & ECT ECU sends current to the solenoid valve S1 and/or S2
Shift Timing Control
based on signals from each sensor and shifts the gear.
The engine & ECT ECU sends current to the shift solenoid valve SL based
Lock-up Timing Control
on signals from each sensor and engages or disengages the lockup clutch.
When the shift lever is shifted from “N” to “D” position, the gear is
“N” to “D” Squat Control
temporarily shifted to 2nd and then to 1st to reduce vehicle squat.
2nd Start Control Enabling the vehicle to take off in the 2nd gear and thus helps to take off on
(SNOW Mode) ice or snow.
The engine and ECT ECU perform shift control upon receiving signals from
Multi-Mode Automatic the transmission control switch (+: up-shift range switch signal and –:
Transmission down-shift range switch signal). This system is the same as that of the U241E.
(See page CH-33)
When the engine & ECT ECU detects a malfunction, the engine & ECT ECU
makes a diagnosis and memorizes the failed section.
Diagnosis
To increase the speed for processing the signals, the 32-bit CPU of the engine
& ECT ECU has been adopted.
Even if a malfunction is detected in the sensors or solenoids, the engine &
Fail-safe ECT ECU effects fail-safe control to prevent the vehicle’s drivability from
being affected significantly.
CH-48 CHASSIS – AUTOMATIC TRANSAXLE
2. Construction
The configuration of the electronic control system in the U341E automatic transaxle is as shown in the
following chart.
SENSORS ACTUATORS
NE S1
CRANKSHAFT POSITION SENSOR SOLENOID VALVE S1
THW
WATER TEMP. SENSOR
S2
SOLENOID VALVE S2
VTA1
THROTTLE POSITION SENSOR
SLT
STA SOLENOID VALVE SLT
NEUTRAL START SWITCH
P, R, N, D
KD
KICK DOWN SWITCH*
SL
SOLENOID VALVE SL
SPD
COMBINATION METER SB
SOLENOID VALVE SB
NT
INPUT TURBINE SPEED SENSOR
COMBINATION METER
STP
STOP LIGHT SWITCH
W CHECK ENGINE
WARNING LIGHT
THO
ATF TEMPERATURE SENSOR
MPX1
SFTU MPX2 S MODE INDICATOR LIGHT
TRANSMISSION CONTROL SWITCH
SFTD, S RANGE POSITION INDICATOR
MPX1
MPX2 SIL
INTEGRATION RELAY DATA LINK CONNECTOR 3
TC
240CH86
*: Europe LHD Model only
CHASSIS – AUTOMATIC TRANSAXLE CH-49
3. Layout of Component
Engine & ECT ECU
Integration Relay
SNOW Mode Switch
Check Engine
Warning Light
CH
SNOW Mode
DLC3 Indicator Light 240CH30
S Mode Indicator
Range Position Light
Stop Light Switch Shift Lever
Kick Down Switch* Indicator
Transmission
Control Switch
240CH29
*: Only for the Engine LHD Models
Solenoid Valve S2
Solenoid Valve S1
Solenoid Valve SB Solenoid Valve ST
240CH26
CH-50 CHASSIS – AUTOMATIC TRANSAXLE
Cross Section
216CH12
CH
3-4
C1
Timing
Valve
4-3
Timing
Valve
Linear Control
Valve SLT Solenoid Valve ST
B1
171CH12
Torqueted rpm
Change Ratio
Engine & Signals from Various Sensors
Input Shaft ECT ECU Engine Speed
Speed Engine Torque Information
Fluid Temp.
Time
Engine
Input Turbine
Speed Sensor SLT
Clutch/Brake
Pressure
Output Shaft
Torque
216CH13
Time
CH-52 CHASSIS – AUTOMATIC TRANSAXLE
Line Pressure
Fluid
Pressure Input Turbine Speed Sensor
Trans- Fluid Temperature
axle
Current Shift Position
161ES26
Shift Program
: Up Shift : Down Shift
Mode Normal Snow
D, S mode 4 1st 2nd 3rd 4th 2nd 3rd 4th
S mode 3 1st 2nd 3rd 2nd 3rd
Shift Position
S mode 2 1st 2nd 3rd 2nd 3rd
S mode 1 1st 2nd 1st 2nd
CHASSIS – AUTOMATIC TRANSAXLE CH-53
1) General
With shifting control in uphill driving, the engine & ECT ECU calculates the throttle opening angle and
the acceleration rate to determine whether the vehicle is in the uphill state. While driving uphill on a
winding road with ups and downs, the 4th upshift is restricted to ensure a smooth drive.
Uphill
Corner CH
2) Uphill Judgment
The actual acceleration calculated from the speed sensor signal is compared with the reference
acceleration stored in the engine & ECT ECU to judge uphill driving.
The engine & ECT ECU judges an uphill condition if the actual acceleration is smaller than the reference
acceleration, and restricts the 3rd to 4th upshift after a 4th to 3rd downshift has occurred.
Reference acceleration
Actual acceleration
Smaller
Uphill 240CH27
CH-54 CHASSIS – AUTOMATIC TRANSAXLE
Fail Safe
This function minimizes the loss of operability when any abnormality occurs in each sensor or solenoid.
When all solenoids are When solenoid valve When solenoid S2 is When solenoid S1 and
Normal S1 is abnormal abnormal S2 are abnormal
Solenoid Solenoid Solenoid Solenoid
Gear Gear Gear Gear
S1 S2 S1 S2 S1 S2 S1 S2
ON
x
ON ON 1st 3rd ON x 2nd x x 3rd
OFF
ON OFF 2nd x OFF 3rd ON x 2nd x x 3rd
OFF OFF 3rd x OFF 3rd OFF x 3rd x x 3rd
OFF ON 4th x ON 4th OFF x 3rd x x 3rd
8. Diagnosis
When the engine & ECT ECU detects a malfunction, it makes a diagnosis and memorizes the failed
section. Furthermore, the check engine warning light in the combination meter illuminates or blinks to
inform the driver.
At the same time, the DTCs (Diagnosis Trouble Codes) are stored in memory. The DTCs can be read by
connecting a hand-held tester. For details, see the Avensis Repair Manual (Pub. No. RM1018E).
Service Tip
The length of time to clear the DTC by disconnecting the battery terminal has been changed from 10
seconds to 1 minute.