ECU TOYOTA CAMRY V20 1986 Service Information

Manual Shifting Test (A140E)
HINT: With this test, it can be determined whether the
trouble lies within the electrical circuit or is a mechani-
cal problem in the transaxle.
1. DISCONNECT ECT ECU CONNECTOR
(a) Remove the glove box.
(b) With the engine OFF, disconnect the ECT connector.
HINT: If the L, 2 and D range gear positions are difficult
to distinguish, perform the following road test.
wWhite driving, shift through the L, 2 and D ranges.
Check that the gear change corresponds to the shift
position.
3. CONNECT ECT ECU CONNECTOR2. INSPECT MANUAL DRIVING OPERATION
Check that the shift and gear positions correspond with
the table below.
Gear position
Shift positionP
' range R
range 2
range V
rangeL
range
Pawl
Lock Reverse
O/D 1st
3rd
± AUTOMATIC TRANSAXLETroubleshooting (Manual Shifting Test) (A140E)AT±23

Disconnect ECT ECU connector and road test.
Does the transaxle operate i n the respective gear
when in the following ranges while driving?
D range . . Overdrive
2 range . . 3 rd gear
L range . . . 1 st gear
TROUBLESHOOTING FLOW±CHART
Trouble No.1 No Shifting
Connect a voltmeter to the check connector termi-
nals Tt and E1.
Does ECT terminal voltage vary with changes in
throttle opening?
Is voltage between ECT ECU terminals
BK and GND as follows?
0V: Brake pedal released
10 ± 14 V: Brake pedal depressed Warm up engine
Coolant temp.: 17f6°F (80°C)
ATF temp.: 122 ± 176°F (50 ± 80°C)
wECU power source and ground faulty
wThrottle position signal faulty
wECT terminal wire open or short
Ye s
Continued on page AT±27Brake signal
faulty
Transaxle faulty Ye s
Ye s
± AUTOMATIC TRANSAXLETroubleshooting (Electronic Control System) (A±1 40E)AT±26

Connect ECT ECU connector and road test.
Does ECT terminal voltage rise from 0V
to 7V in sequence?
Are there battery voltage between
ECT ECU terminals 2 ± GND
when in the D range?
Are there battery voltage between ECT ECU
terminals L ± GND when in the D range?
Neutral start switch circuit faulty
Neutral start switch faultyProceed to trouble 3
(See page AT±29) Continued from page AT±26
Transaxle faulty
Solenoid faulty
Try another ECT ECU.0
7V
0
3V0
5V
Ye sYe s
± AUTOMATIC TRANSAXLETroubleshooting (Electronic Control System) (A140E)AT±27

Connect a voltmeter to the check connector
terminals Tt and El.
Does ECT terminal voltage vary with changes in throttle
opening?
Check voltage between ECT ECU terminals
PWR and GND.
Power pattern: 10 ± 14V
Normal pattern: 1VIs voltage between ECT ECU terminals
BK and GND as follows?Tt
0V: Brake pedal released
10 ± 14V: Brake pedal depressed Warm up engine
Coolant temp.: 176°F (80°C)
ATF temp.: 122 ± 176°F (50 ± 80°C)
wECU power source and ground faulty
wThrottle position signal faulty
wECT terminal wire open or short
Faulty pattern select switch system
Shift point too high or too low
wFaulty ECT ECU
w|Faulty transaxle
Trouble No. 2
Brake sig-
nal faulty Ye s
Ye s
± AUTOMATIC TRANSAXLETroubleshooting (Electronic Control System) (A140E)AT±28

Is voltage between terminals OD2 and GND as fol-
lows?
O/D switch turn ON: 10 ± 14V
O/D switch turn OFF: 0VRoad test while shifting manually with ECT
ECU connector disconnected.
Is there overdrive up±shift in the D range when
shifting from L to 2 to D?
Is voltage between terminals OD, and GND as fol-
lows?
Approx. 5 V
Is voltage between ECT ECU terminals
OD, and GND normal with the cruise control com-
puter connector pulled out?Connect ECT ECU connector, and while driving
does ECT terminal voltage rise from
0V to 7V in sequence?
No up±shift to overdrive (After warm±up)
Are there battery voltage between
ECT ECU terminals L and GND
when in the D range?Are there battery voltage between
ECT ECU terminals 2 and
GND when in the D range?
wFaulty neutral start switch circuit
wFaulty neutral start switch
Faulty ECT ECU
Faulty cruise control wire harnessFaulty O/D switch harness
Faulty O/D switch
Faulty cruise control computer±Faulty transaxle
Faulty solenoid
Try another ECT ECU
Try another ECT ECUFaulty transaxle
Trouble No. 3
Ye sYe s
Ye s
Ye sYe sYe s
± AUTOMATIC TRANSAXLETroubleshooting (Electronic Control System) (A140E)AT±29

Road test
Connect a voltmeter to the check connector
terminals Tt and El.
Is there 7, 5 or 3 V in the lock±up range while driving?
Is voltage between ECT ECU Terminals
BK and GND as follows?
Brake pedal depressed: 10 ± 14V
Brake pedal released: 0V Warm up engine ,
Coolant temp.: 176°F (80°C)
ATF temp.: 122 ± 176°F (50 ± 80°C)
wLock±up solenoid stuck
wFaulty transmission
wFaulty lock±up mechanism
wFaulty ECU power source and ground
w Faulty throttle position signal
No lock±up (After warm±up)
Faulty brake signal Trouble No. 4
Ye s
Ye s
± AUTOMATIC TRANSAXLETroubleshooting (Electronic Control System) (A140E)AT±30

INSPECTION ELECTRONIC CONTROL
COMPONENTS
1. INSPECT VOLTAGE OF ECT ECU CONNECTOR
(a) Remove the glove box and instrument panel.
(b) Turn on the ignition switch.
(e) Measure the voltage at each terminal.
Throttle valve fully closed to fully open Throttle valve fully closed to fully open
Throttle valve fully closed to fully open
Vehicle moving (Cruise control OFF)Standing still (Cruise control OFF) Throttle valve opening above 1 .5°
When brake pedal is not depressed When brake pedal is depressed Throttle valve fully closed Throttle valve fully closed
Throttle valve fully closed
Throttle valve fully closed Throttle valve fully open Throttle valve fully open Throttle valve fully openMeasuring condition
Except L range
Except N range Except 2 rangeVoltage (V)
Terminal
N range 2 range
L range
± AUTOMATIC TRANSAXLETroubleshooting (Electronic Control System) (A140E)AT±32

(Assembly of Valve Body)
(See page AT±121)
1. POSITION PLATE AND NEW GASKETS ON LOWER
VALVE BODY
Position the new No. 2 gasket, the plate and then the new
No. 1 gasket on the lower valve body.
HINT: Since No. 1 gasket and No. 2 gasket are similar use
the illustration below to discriminate between them.
2. PLACE LOWER VALVE BODY WITH PLATE AND
GASKETS ON UPPER VALVE BODY
HINT: Hold the lower valve body, gaskets and plate
securely so they do not separate.
Align each bolt hole in the valve bodies with the gas-
kets and plate.
3. INSTALL AND FINGER TIGHTEN BOLTS IN LOWER
VALVE BODY TO SECURE UPPER VALVE BODY
Install and finger tighten the three bolts.
HINT: Each bolt length (mm (in.)) is indicated in the
figure.
± AUTOMATIC TRANSAXLEComponent Parts (Valve Body) (A140E)AT±130

(A540H)
The A540H automatic transaxle design is based on the A540E automatic transaxle and equipped with
a center differential and transfer.
This transaxle has the same hydraulic multiplate clutch in the center differential limiting control mecha-
nism as the A241 H automatic transaxle on the Corolla All±TRAC/4WD Station Wagon. The fluid pres-
sure acting on the hydraulic multiplate clutch of the A540H is controlled by the ECT ECU (Electronic
Control Unit according to the vehicle driving conditions. As a result, torque is distributed to the front
and rear wheels appropriately at all times to maximize the overall performance of the 4WD vehicle.
NOTICE: Special handling methods are necessary for full±time 4WD vehicles during inspection and mainte-
nance. Instructions concerning these handling methods are given on page IN±8.
± AUTOMATIC TRANSAXLEDescription (A540E and A540H)AT±185

( ) 1: No fail±safe function X: Malfunctions
HINT: (A540H) When any one of the speed sensors (front or rear) or center differential control sole-
noid valves (No. 1 or No. 2) malfunction, the ECT ECU stops center differential control and main-
tains the center differential in a free condition.
Operating Mechanism for Each Gear (A540E A540H)
1. CLUTCH BRAKE AND ONE±WAY CLUTCH
A540E, A540H
Down±shift only ± no up±shift
2. SOLENOID SYSTEM
Possible gear positions in accordance with solenoid operating conditions.
A540E, A540H
NO. 2 SOLENOID
MALFUNCTIONING NO. I SOLENOID
MALFUNCTIONINGBOTH SOLENOIDS
MALFUNCTIONING Shift lever
positionGear position
NORMAL
D rangeParking
2 range
L rangeReverse
Neutral
Range
2nd3 rd
O/D
2nd1st
1st 1st2nd
3rd
± AUTOMATIC TRANSAXLETroubleshooting (Operating Mechanism for Each Gear
(A540E and A540H)AT±189