Page 474 of 2389
Road test
Connect a voltmeter to terminals Tt and El.
Is there 7, 5 or 3V in the lock±up range while driv-
ing?
Is voltage between Engine and ECT ECU BK
and E1 terminals as follows?
Brake pedal depressed: 10 ± 14V
Brake pedal released: OV Warm up engine
Coolant temp.: 176°F (80°C)
ATF temp.: 122 ± 176°F (50 ± 80°C)
wFaulty ECU power source and ground
wFaulty throttle position signalwLock±up solenoid stuck
wFaulty transaxle
w Faulty lock±up mechanism
No lock±up (After warm±up)
Faulty brake signal
Trouble No. 4
Ye sYe s
± AUTOMATIC TRANSAXLETroubleshooting (Electronic Control System) (A540E and
A540H)AT±210
Page 475 of 2389

Disconnect solenoid wire connector and road test.
Does the transaxle operate in the respective gear
when in the following ranges white driving?
D range .... Overdrive
2 range .... Overdrive
L range .... 1 st gear
TROUBLESHOOTING FLOW±CHART (A540H)
Trouble No. 1 No Shifting
Is voltage between ECT ECU terminals BK
and GND as follows?
0V: Brake pedal released
10 ± 14V: Brake pedal depressed
Connect solenoid wire connector and road test.
Does Tt terminal voltage rise from OV to 7V in se-
quence?Warm up engine
Coolant temp.: 176°F (80°C)
ATF temp.: 122 ± 176°F (50 ± 80°)
Connect a voltmeter to terminals Tt and E1.
Does Tt terminal voltage vary with changes in
throttle opening? (See page AT±215)
wECU power source and ground faulty
wThrottle position signal faulty
wTt terminal wire open or short
Are there 10 ± 14V between ECT
ECU terminals 2L ± GND when in the
D range?
Are there 10 ± 14V between ECT ECU
terminals LL ± GND when in the D range?
wNeutral start switch circuit faulty
wNeutral start switch faultyProceed to trouble No. 3
(See page AT±227) Transaxle faulty
Solenoid faulty
Try another ECT ECUBrake signal
faulty
Transaxle faulty
Ye s
Ye s
Ye s Ye s
Ye s
± AUTOMATIC TRANSAXLETroubleshooting (Electronic Control System) (A540E and
A540H)AT±211
Page 476 of 2389
Is voltage between ECT ECU terminals BK
and GND as follows? .
0V: Brake pedal released
10 ± 14V: Brake pedal depressed
Check voltage between ECT ECU terminals
P and GND.
Power pattern: 10 ~ 14V
Normal pattern: 1 V Warm up engine
Coolant temp.: 176°F (80°C)
ATF temp.: 122 ± 176°F (50 ± 80°C)
Connect a voltmeter to terminals Tt and E1.
Does Tt terminal voltage vary with changes in
throttle opening? (Seepage AT±21 5)
ECU power source and ground faulty
Throttle position signal faulty
Tt terminal wire open or short
Faulty pattern select switch system
Shift point too high or too low
Faulty ECT ECU
Faulty speed sensorBrake signal
faulty
Trouble No. 2
Ye s
Ye s
± AUTOMATIC TRANSAXLETroubleshooting (Electronic Control System) (A540E and
A540H)AT±212
Page 478 of 2389
Road test
Connect a voltmeter to terminals Tt and E,.
Is there 7, 5 or 3V in the lock±up range while driv-
ing?
Is voltage between ECT ECU BK and GND
terminals as follows?
Brake pedal depressed: 10 ± 14V
Brake pedal released: OV Warm up engine
Coolant temp.: 176°F (80°C)
ATF temp.: 122 ± 176°F (50 ± 80°C)
Trouble No. 4 No lock±up (After warm±up)
w Lock±up solenoid stuck
wFaulty transaxle
wFaulty lock±up mechanism
wFaulty ECU power source and ground
wFaulty throttle position signalFaulty brake signal
Ye sYe s
± AUTOMATIC TRANSAXLETroubleshooting (Electronic Control System) (A540E and
A540H)AT±214
Page 479 of 2389

3. INSPECT EACH UP±SHIFT POSITION
(a) Warm up the engine.
Coolant temperature: 176
°F (80°)
(b) Turn the O/D switch to ºONº.
(c) Place the pattern select switch in ºNormalº and the shift
lever into the D range.
(d) During a road test (above 10 km/h or 6 mph) check that volt-
age at the Tt terminal is as indicated below for each up±
shift position.
If the voltage rises from 0V to 7V in the sequence shown,
the control system is okay.
The chart on the left shows the voltmeter reading and cor-
responding gears.
HINT: Determine the gear position by a fight shock or
change in engine rpm when shifting. The lock±up clutch will
turn ON only infrequently during normal 2nd and 3rd gear
operation. To trigger this action, press the accelerator pedal
to 50% or more of its stroke. At less than 50%, the voltage
may change in the sequence 2v ± 4V ± 6V ± 7V. 2. INSPECT BRAKE SIGNAL
(a) Depress the accelerator pedal until the Tt terminal indi-
cates 8V.
(b) Depress the brake pedal and check the voltage read-
ing from the Tt terminal.
Brake pedal depressed ...... 0V
Brake pedal released . . . . . . . . 8V
If not as indicated, there is a malfunction in either the
stop light switch or circuit.
INSPECTION OF ECT OR Tt TERMINAL
VOLTAGE
1. INSPECT THROTTLE POSITION SENSOR SIGNAL
(a) Turn the ignition switch to ON. Do not start the engine.
(b) Connect a voltmeter to terminals Tt and E1.
(c)while slowly depressing the accelerator pedal, check
that Tt terminal voltage rises in sequence.
If the voltage does not change in proportion to the
throttle opening angle, there is a malfunction in the
throttle position sensor or circuit.
± AUTOMATIC TRANSAXLETroubleshooting (Electronic Control System) (A540E and
A540H)AT±215
Page 482 of 2389
3. (A540E)
INSPECT SOLENOID VALVES
(a) Disconnect the connector from Engine and ECT ECU
(b) Measure the resistance between S1, S2, SL and
body ground.
Resistance: 11 ± 15
(e) Apply battery voltage to each terminal.
Check that an operation noise can be heard from
the solenoid.
Center differential control switch AUTO position
Center differential control switch AUTO position Center differential control switch turned OFF
Center differential control switch turned OFF Coolant temp. below 122°F950°0 Throttle valve fully closed to fully open
Coolant temp. above 122°F (50°C0 O/D main switch turned OFF O/D main switch turned ON
Brake pedal is depressed
Brake pedal is releasedMeasuring condition
Except 2 range
Except N range Except P range
Except L range
NORM patternVoltage (V)
PWR pattern Terminal
N range2 range P range
L range
± AUTOMATIC TRANSAXLETroubleshooting (Electronic Control System) (A540E and
A540H)AT±218
Page 486 of 2389

INSTALLATION OF THROTTLE CABLE
1. INSTALL CABLE INTO TRANSMISSION CASE
2. INSTALL VALVE BODY
3. IF THROTTLE CABLE IS NEW, STAKE STOPPER OR
PAINT MARK ON INNER CABLE
HINT: New cable do not have a cable stopper staked.
(a) Bend the cable so there is a radius of about 200 mm(7.87 in.).
(b) Pull the inner cable lightly until a slight resistance is felt, and hold
it.
(e) Stake the stopper, 0.8 ± 1.5 mm (0.031 ± 0.059 in.)
from the end of outer cable.
4. CONNECT THROTTLE CABLE TO ENGINE
5. ADJUST THROTTLE CABLE (See page AT±201)
6. INSTALL AND ADJUST NEUTRAL START SWITCH
7. TEST DRIVE VEHICLE
Throttle Cable
REMOVAL OF THROTTLE CABLE
1. DISCONNECT THROTTLE CABLE FROM ENGINE
2. REMOVE NEUTRAL START SWITCH
3. REMOVE VALVE BODY
4. REMOVE THROTTLE CABLE
ON±VEHICLE REPAIR
HINT: The components mentioned below can be replaced on the vehicle without any necessity for
removal of the transaxle. For the respective operating procedures refer to the following pages:
Speedometer driven gear oil
seal
Extension housing oil
seal Side gear
shaft oil sealAT±232 and AT±233 AT±242 to AT±244
Throttle cable
Only A540H Components
Valve bodyInstallation
RemovalRemarks
AT±231AT±231
AT±233AT±232
AT±233AT±232
AT±232
± AUTOMATIC TRANSAXLEOn±Vehicle Repair (A540E and A540H)AT±231
Page 489 of 2389
REMOVAL AND INSTALLATION OF TRANSAXLE
(A540E and A540H)
REMOVAL AND INSTALLATION OF ENGINE
(3S±FE: See pages EM±106 and EM±t30, 2VZ±FE: EM±138 and EM±165)
REMOVAL AND INSTALLATION OF TRANSAXLE
(Remove and install transaxle as shown)
± AUTOMATIC TRANSAXLERemoval and Installation of Transaxle (A540E and
A540H)AT±234