Page 49 of 2389
AT0376
SST
AT0194
SST
AT3571
AT0196 AT4168
(e) Remove the overdrive clutch apply gasket and
overdrive brake apply gasket.
47. REMOVE FIRST AND REVERSE BRAKE PISTON
(a) Remove the piston return spring.
Place SST, and compress the return spring
evenly by tightening the bolt gradually.
SST 09350-32014 (09351-32040)
Using snap ring pliers, remove the snap ring.
Remove SST.
Remove the return spring from the case.
(b) Apply compressed air into the passage of the case
to remove the piston.
HINT: Hold the piston so it is not slanted and blow with
the gun slightly away from the oil hole.
(c) If the piston does not pop out with compressed
air, use needle-nose pliers to remove it.
AT-30- AUTOMATIC TRANSAXLERemoval of Component Parts
Page 83 of 2389
AT3063
AT2523
AT7719
AT7720
Printed
Numbers
AT2745
DISASSEMBLY OF OVERDRIVE BRAKE
1. REMOVE PISTON RETURN SPRING
(a) While pushing the return spring, remove the snap
ring with a screwdriver.
(b) Remove the piston return spring.
2. REMOVE PLATES, DISCS AND FLANGE
3. REMOVE PISTON FROM DRUM
Apply compressed air to oil hole to remove the piston.
HINT: Blow with the gun slightly away from the oil hole,
and be careful that the piston dose not tilt.
4. REMOVE O-RINGS
Remove the inner and outer O-rings from the piston.
INSPECTION OF OVERDRIVE BRAKE
INSPECT DISCS, PLATES AND FLANGE
Check if the sliding surfaces of the discs, plates and
flange are worn or burnt. If necessary, replace them.
HINT:
If the lining of the disc is exfoliated or discolored,
or even a part of the printed numbers are defaced,
replace all discs.
Before assembling new discs, soak them in ATF
for at least fifteen minutes.
AT-68- AUTOMATIC TRANSAXLEComponent Parts (Overdrive Unit)
Page 157 of 2389
AT3737
C1
B2C2
AT3539
SpringFree length
mm (in.)Outer diameter
mm (in.)Color
C
251.0 (2.008)18.0 (0.709)
Red
B
258.5 (2.303)15.2 (0.598)
Orange
C
1
Outer71.2 (2.803)24.4 (0.961)
Blue
Inner43.4 (1.709)17.8 (0.701)
Light green
AT3537
AT3536 AT3538
30. INSTALL ACCUMULATOR PISTONS AND SPRINGS
(a) Install the new O-rings to the pistons.
(b) Install the springs and pistons into the bores.
(c) Place the cover with a new gasket and gradually
tighten the bolts a little a time in sequence.
HINT: Each bolt length (mm, in.) is indicated in the figure.
Torque: 100 kg-cm (7 ft-lb, 10 N-m)
31. PLACE NEW SECOND BRAKE APPLY GASKET
32. INSTALL THROTTLE CABLE AND SOLENOID WIRE
33. INSTALL VALVE BODY TO TRANSAXLE CASE
(a) While holding the cam down with your hand, slip
the cable end into the slot.
(b) Lower the valve body into place.
NOTICE: Do not entangle the solenoid wire.
- AUTOMATIC TRANSAXLEInstallation of Component PartsAT-141
Page 266 of 2389

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
Page 271 of 2389

Diagnosis System (A140E)
DESCRIPTION
1. A self±diagnosis function is built into the electrical control system.
Warning is indicated by the overdrive OFF indicator.
HINT: Warning and diagnostic codes can be read only when
the overdrive switch is ON. If OFF, the overdrive OFF
indicator is lit continuously and will not blink.
(a) If a malfunction occurs within the speed sensors (No.
1 or 2) or solenoids (No. 1 or 2), the overdrive OFF
light will blink to. warn the driver. .
However, there will be no warning of a malfunction with
lock±up solenoid.
(b) The diagnostic code can be read by the number of blinks of
the overdrive OFF indicator when terminals
Tt and E1 are short±circuited. (See page AT±17)
tc) The throttle position sensor or brake signal are not indi-
cated, but inspection can be made by checking the voltage at
terminal Tt of the check connector (diagnosis).
(d) The signals to each gear can be checked by measuring the
voltage at terminal Tt of the check connector while driving.
2. The diagnostic (malfunction) code is retained in memory by the
CPU and due to back±up voltage, is not canceled out when the
engine is turned off. Consequently, after repair, it is necessary
to turn the ignition switch off and remove the fuse EFI (15A) or
disconnect the ECT computer connector to cancel out the diag-
nostic (malfunction)
code. (See page AT±18)
HINT:
wLow battery voltage will cause faulty operation of the diag-
nosis system. Therefore, always check the battery first.
w Use a voltmeter and ohmmeter that have an impedance
of at least 10 k 11 IV.
CHECK O/D OFF INDICATOR LIGHT
1. Turn the ignition switch ON.
2. The O/D OFF light will come on when the O/D switch is
placed at OFF.
3. When the O/D switch is set to ON, the O/D OFF light
should go out.
If the O/D OFF light flashes when the O/D switch is set
to ON, the electronic control system is faulty.
± AUTOMATIC TRANSAXLETroubleshooting (Diagnosis System) (A140E)AT±16
Page 288 of 2389

3. INSPECT EACH UP±SHIFT POSITION
(a) Warm up the engine.
Coolant temperature: 176
°F (80°C)
(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
voltage at the ECT 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
corresponding gears. .
HINT: Determine the gear position by a light 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 acceler-
ator 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 ECT terminal
indicates 8V.
(b) Depress the brake pedal and check the voltage read-
ing from the ECT terminal.
(c) 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 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 ECT 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) (A140E)AT±31
Page 292 of 2389
(e) Turn the O/D switch ON.
(d) Select the normal pattern.
(e) Drive .at around 50 km/h (31 mph) to where 7, 5 or 3
volts appears on the voltmeter (this is the lock±up
range) .
(f) Depress the accelerator pedal and read the tachometer.
If there is a big jump in engine rpm there is not lock±
up. 8. INSPECT PATTERN SELECTION SWITCH
Inspect that there is continuity between 5 and each ter-
minal. .
HINT: As there are diodes inside, be careful of the test-
er probe polarity.
10. INSPECT LOCK±UP MECHANISM
(a) Warm up the coolant and ATF.
(b) Connect a voltmeter to the check connector terminals
Tt and E1.
11. INSPECT BRAKE SIGNAL
Check that the brake light comes on when the brake
pedal is depressed. 9. INSPECT O/D SWITCH
Inspect that there is continuity between terminals 1 and 3.
S/W positionTerminal
Terminal Pattern
NORM
PWR
OFF
± AUTOMATIC TRANSAXLETroubleshooting (Electronic Control System) (A140E)AT±35
Page 299 of 2389

2. 2 RANGE TEST
Shift into the 2 range and, while driving with the accel-
erator pedal held constantly at the full throttle valve
opening position, push in one of the pattern selectors
and check on the following points.
(a) Check to see that the 1 ±2 up±shift takes place and
that the shift point conforms to it shown on the auto-
matic shift schedule. (See page AT±49)
(b) White running in the 2 range and 2nd gear, re-
lease the accelerator pedal and check the en-
gine braking effect.
EVALUATION
If there is no engine braking effect:
wSecond coast brake is defective (d) While running in the D range, 2nd, 3rd and O/D
gears, check to see that the possible kick±
down vehicle speed limits for 2 ±1, 3 ±2 and O/D
±3 kickdowns conform to those indicated on the
automatic shift schedule. (See page AT±49)
(e) Check for abnormal shock and slip at kick±down.
(f) Check for the lock±up mechanism:
(1) Drive in D range ± O/D gear, at a steady speed
(lock±up ON) of about 75 km/h (47 mph).
(2) Lightly depress the. accelerator pedal and check
that the engine rpm does not change abruptly.
If there is a big jump in engine rpm, there is no
lock±up.
(e) Check for abnormal noise at acceleration and
deceleration, and for shock at up±shift and
downshift.
± AUTOMATIC TRANSAXLETroubleshooting (Mechanical System Tests) (A140L and
A140E)AT±44