TOYOTA CAMRY V20 1986 Service Information

A140L Automatic Transaxle
CONSTRUCTION AND OPERATION
The A140L automatic transaxle can be roughly divided into the automatic transmission section and the
differential section. The automatic transmission section is composed of the torque converter, planetary
gear unit and the hydraulic control system.
OPERATION
The pump impeller is rotated by the engine, which
causes a flow in the ATF inside the torque converter.
The flow of ATF caused by the pump impeller strikes
the turbine runner, providing a force to rotate the tur-
bine runner, and transmits torque to the input shaft.
The flow of ATF which has hit the turbine runner re-
bounds and tries to flow in the direction opposite to
the direction of rotation of the pump impeller, but the
stator returns the flow the original direction of rotation.
So the ATF
becomes a force which supports the pump impeller
and increases torque.
HINT: Although the stator is immobilized by the one-
way clutch, should the one±way clutch become de-
fective the stator will be rotated by the flow of ATF,
the flow of
ATF will not be reversed, torque will not be increased
and the problem of inadequate acceleration will occur.
The lock±up clutch is pushed against the front cover
by fluid pressure so that the engine revolutions are
directly transmitted to the input shaft without the me-
dium of the
AT F.
1. Torque Converter
CONSTRUCTION
The torque converter is composed of the pump impeller
which is rotated by the engine, the turbine runner and
lock±up clutch which are fixed to the transmission input
shaft, and the stator which is attached to the stator
shaft via the one±way clutch.
The torque converter is filled with ATF.
± AUTOMATIC TRANSAXLEDescription (A140L and A140E)AT±5

2. Planetary Gear Unit
CONSTRUCTION
The planetary gear unit is composed of three sets of planetary gears, three clutches which transmit
power to the planetary gears, and four brakes and three one±way clutches which immobilize the
planetary carrier and planetary sun gear.
± AUTOMATIC TRANSAXLEDescription (A140L and A140E)AT±6

OPERATION
Power from the engine transmitted to the input shaft via the torque converter is then trans-
mitted to the planetary gears by the operation of the clutch.
By operation of the brake and one±way clutch, either the planetary carrier or the planetary sun
gear are immobilized, altering the speed of revolution of the. planetary gear unit.
Shift change is carried out by altering the combination of clutch and brake operation.
Each clutch and brake operates by hydraulic pressure; gear position is decided according to
the throttle opening angle and vehicle speed, and shift change automatically occurs.
The conditions of operation for each gear position are shown on the following illustrations:
± AUTOMATIC TRANSAXLEDescription (A140L and A140E)AT±7

3. Hydraulic Control System
CONSTRUCTION
The hydraulic control is composed of an oil pump, rotated by the engine, which supplies hydraulic pres-
sure; a valve body which controls the hydraulic pressure and the opening and closing of the fluid pas-
saged; and a governor valve which supplies hydraulic pressure in accordance with vehicle speed.
OPERATION
Hydraulic pressure supplied by the oil pump is controlled± by the regulator valve; the resulting oil pres-
sure controlled by the regulator valve is called the line pressure.
Line pressure produces the hydraulic pressure for throttle pressure and governor pressure. Also, line
pressure produces hydraulic pressure for the operation of each brake and clutch in the planetary gear
unit.
The throttle valve acts to produce hydraulic pressure, called the throttle pressure, which responds to ac-
celerator pedal modulation. Throttle pressure increases as the accelerator pedal is depressed.
The governor valve produces hydraulic pressure, called the governor pressure, in response to vehicle
speed. Governor pressure increases as vehicle speed increases.
In accordance with the difference between throttle pressure and governor pressure, each shift valve
shifts, the fluid passages to the clutches are brakes in the planetary gear unit are opened and the
clutches and brakes operate, and shift change occurs.
The operation of the hydraulic control system, using the 2±3 shift valve as an example, is shown below;
± AUTOMATIC TRANSAXLEDescription (A140L and A140E)AT±8

A140E Automatic Transaxle (ECT)
WHAT IS THE ECT?
ECT means Electronic Controlled Transaxle. The hydraulic control system of the previous automatic
transaxle has been changed, the throttle and governor pressure have been replaced by electronic
signals and a micro computer has been used to give precise control of shift timing and lock±up tim-
ing.
FEATURES OF THE ECT
(a) The shift pattern can be chosen.
In the ECT ECU micro computer used in the A140E, two types of shift pattern, Power and Normal,
are recorded in the memory. By operating the pattern select switch, the driver can select the pre-
ferred shift pattern.
(b) Reduced fuel consumption and reduced shock during shifting is made possible.
Precise control of the shift timing by the ECT ECU, operation of the lock±up clutch from low speeds,
and decreased fuel consumption are made possible. Also, shock during Shifting is reduced.
(e) Self±Diagnostic System
When a malfunction occurs in the electronic control system, the driver is informed of this fact. Also,
there is a Self±Diagnostic System which displays the location of the malfunction when the service
connector is shorted.
(d) Fail±Safe System
A fail±Safe System is included so that, even if a malfunction occurs in the electronic control system,
the vehicle will be able to operate.
CONSTRUCTION AND OPERATION
When the A140E (ECT) is compared with the A140L, the automatic transaxle body has the same
construction and operation, with the exception of the hydraulic control system, as the A140L.
The electronic control system, which controls the shift timing and lock±up timing, has been added.
1. Hydraulic Control System (Comparison with the A140L)
VALVE BODY ± Additions or changes to solenoid valve
In the A140E there are three solenoid valves, the No. 1, the No. 2 and the lock±up solenoid valves.
Shifting occurs according to whether the No. 1 and No. 2 solenoid valves are ON or OFF, and the
lock±up solenoid valve controls the lock±up clutch.
GOVERNOR VALVE ± Removed
With the A140E, the governor valve has been replaced with a speed sensor, so that instead of the
governor pressure, a speed sensor signal is sent to the ECT ECU.
SHIFT CONTROL IN ECT
1. The vehicle speed is sensed by the vehicle speed
sensor, which sends this data to the
ECU in the form of electrical signals.
2. The angle to which the throttle is open is sensed
by the throttle position sensor, which sends this
data to the ECU in the form of electrical signals.
3. The ECT computer determines the shift point on
the basis of these two signals and operates the
solenoid valves in the hydraulic control unit, thus
shifting the transmission.
± AUTOMATIC TRANSAXLEDescription (A140L and A140E)AT±9

2. Electronic Control System
COMPONENTS
The electronic control system for controlling the shift timing and the operation of the lock±up clutch
is composed of the following three parts:
(a) Sensors: These sense the vehicle speed and throttle position and send this data to the ECT ECU
in the form of electronic signals.
(b) ECT ECU: This determines the shift and lock±up timing based upon the signals from the. sensors.
(e) Actuators: Solenoid valves divert hydraulic pressure from one circuit of the hydraulic control unit
to another, thus controlling shifting and lock±up timing.
VEHICLE SPEED SENSOR
NO. 1 AND NO. 2
BRAKE LIGHT SWITCH
O/D MAIN SWITCH
THROTTLE POSITION
SENSOR
CRUISE CONTROL
COMPUTER PATTERN SELECT
SWITCH
NEUTRAL START
SWITCH
LOCK±UP SOLE±
NOID VALVE NO. 2 SOLENOID
VA LV E NO. 1 SOLENOID
VA LV E
Control of shift
tinning
Self±diagnostic
systemControl of lock±up
timing
WATER TEMP.
SENSORO/D OFF INDI±
CATOR LIGHT Back±up system
ECT ECU
ENGINE
ECU
ACTUATOR
SENSOR ACTUATOR
± AUTOMATIC TRANSAXLEDescription (A140L and A140E)AT±10

Shift cable out of adjustment
Valve body or primary regulator
faulty
Parking lock pawl faulty
Torque converter faulty
Converter drive plate broken
Oil pump intake screen blocked
Transaxle faulty
Shift cable out of adjustment
Throttle cable out of adjustment
Valve body faulty
Solenoid valve faulty
Transaxle faulty Throttle cable out of adjustment
Valve body or primary regulator faulty
Accumulator pistons faulty
Transaxle faultyInspect parking lock pawl
Replace torque converter
Replace drive plate
Clean screen
Disassemble and inspect
transaxle
Adjust shift cable
Adjust throttle cable
Inspect valve body
Inspect solenoid valve
Disassemble and inspect
transaxle
General Troubleshooting
Delayed 1±2, 2±3 or
3±O/D up±shift, or
down±shifts from
O/D±3 or 3±2 and
shifts back to O/D or 3Replace fluid
Replace torque converter
Disassemble and inspect
transaxle
Adjust shift cable
Inspect valve body
Disassemble and inspect
transaxle
Adjust shift cable
Inspect valve body
Disassemble and inspect
transaxle Shift cable out of adjustment
Manual valve and lever faulty
Transaxle faulty
Shift cable out of adjustment
Valve body faulty
Transaxle faultyInspect electronic control
Inspect valve body
Inspect solenoid valve Inspect accumulator pistons
Disassemble and inspect
transaxle
Electronic control faulty
Valve body faulty
Solenoid valve faulty Fluid contaminated
Torque converter faulty
Transaxle faulty
Slips on 1±2, 2±3
or 3±O/D up±shift,
or slips or shudders
on acceleration Vehicle does not
move in any forward
range or reverse
Drag, binding or tieup on
1±2, 2±3 or
3±4/D up±shift Harsh engagement into
any drive range
AT±22
AT±22
AT±133
AT±56 Adjust throttle cable
Inspect valve body
AT±121
AT±33 Adjust shift cable
Inspect valve body
Shift lever position
incorrect Fluid discolored or
smells burntAT±21
AT±156
AT±56
AT±22
AT±133
AT±56 AT±22
AT±133
AT±56
AT±24
AT±121
AT±33 AT±36
AT±133 AT±177
AT±56AT±121
AT±121 AT±22
AT±133
AT±22
AT±133 AT±72
AT±156 Possible cause
AT±121
AT±121 Problem
Remedy
A140E
A140LPage
AT±56
± AUTOMATIC TRANSAXLETroubleshooting (General Troubleshooting) (A140L. and
A140E)AT±12

Adjust throttle cable
Inspect throttle cable and cam
Inspect accumulator pistons
Inspect valve body
Disassemble and inspect
transaxle
Inspect throttle cable
Inspect valve body
Disassemble and inspect
transaxle
Inspect solenoid valve
Inspect electronic control
Inspect solenoid valve
Inspect electronic control
Inspect valve body
Disassemble and inspect
transaxleInspect electronic control
Inspect valve body
Inspect solenoid valve
Disassemble and inspect
transaxle
Solenoid valve faulty
Electronic control faulty
Valve body faulty
Transaxle faultyElectronic control faulty
Valve body faulty
Solenoid valve faulty
Transaxle faulty
General Troubleshooting (Cont'd)
Shift cable out of adjustment
Parking lock pawl cam and spring
faultyAccumulator pistons faulty
Valve body faulty
Transaxle faulty
Inspect valve body
Inspect solenoid valve
Inspect electronic control
Inspect solenoid valve
Inspect electronic control
Inspect valve body Solenoid valve faulty
Electronic control faulty
Valve body faultyValve body faulty
Solenoid valve faulty
Electronic control faultyThrottle cable out of adjustment
Throttle cable and cam faulty
Throttle cable faulty
Valve body faulty
Transaxle faulty Down±shift occurs too
quickly or too late while
coasting
Solenoid valve faulty
Electronic control faulty
Adjust shift cable
Inspect cam and spring No down±shift when
coastingAT±36
AT±133
AT±56
AT±33
AT±24
AT±121 No engine brak-
ing in 2 or L
rangeAT±24
AT±121
AT±33
AT±36
AT±133
AT±56 No lock±up in
2nd,
3rd or O/D
No O/D±3, 3±2 or
2±1 kick±down
Vehicle does not hold
in PAT±177
AT±133
AT±56
AT±121
AT±33
AT±24 AT±133
AT±36
AT±22
AT±133
AT±56
AT±33
AT±24
AT±121 AT±36
AT±133AT±121 AT±121 Harsh down±shiftPossible cause
AT±33
AT±24
AT±22
AT±72AT±22
AT±22
AT±36A140E Problem
Remedy
A140LPage
± AUTOMATIC TRANSAXLETroubleshooting (General Troubleshooting) (A 1 40L and
A140E)AT±13

Operating Mechanism for Each Gear (A140L A140E)
1. CLUTCH BRAKE AND ONE±WAY CLUTCH
'Down±shift only ± no up±shift `Down±shift only ± no up±shift
Shift lever
position Shift lever
positionGear position
Gear Position
Parking Parking
Reverse
A140L
Reverse
A140E
Neutral Neutral
2nd2nd
3rdO/D
O/D2nd
2nd2nd
1 st
2nd1 st
1 st3rd
1 st1 st
3rd
± AUTOMATIC TRANSAXLETroubleshooting (Operating Mechanism ± for Each Gear)
(A140L and A140E)AT±14

2. SOLENOID SYSTEM (A140E)
Possible gear positions in accordance with solenoid operating conditions.
A140E
NO. 1 SOLENOID
MALFUNCTIONINGNO. 2 SOLENOID
MALFUNCTIONINGBOTH SOLENOID
MALFUNCTIONING
( ) : No fail safe functionx: Malfunctions
D range
2 rangeNORMAL
L. range Range
± AUTOMATIC TRANSAXLETroubleshooting Operating Mechanism for Each Gear)
(A140L and A140E)AT±15