TOYOTA SUPRA 1995 Service Repair Manual

INSPECTION PROCEDURE
Check sensor resistance
Remove A/T fluid temp. sensor.
Measure resistance between terminals of A/T fluid
temp. sensor at 20°C (68°F) and 110°C (230°F).
Resistance:
20°C (68°F) Approx. 12.08 k

110°C (230°F) Approx. 0.78 k

Replace A/T fluid temp. sensor.
Repair or replace harness or connector.
Check harness and connector between battery and A/T fluid temp. sensor
A/T fluid temp. sensor and ECM. (See page IN±30).
Check A/T fluid temp. sensor.
Check and replace ECM. AT1±65
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTING

DTC 42 No. 1 Vehicle Speed Sensor Signal Circuit
CIRCUIT DESCRIPTION
The No. 1 vehicle speed sensor outputs a 4±pulse signal for every revolution of the rotor shaft, which
is rotated by the transmission output shaft via the driven gear. After this signal is converted into a more
precise rectangular waveform by the waveform shaping circuit inside the combination meter, it is then
transmitted to the ECM. The ECM determines the vehicle speed based on the frequency of these pulse
signals.
All conditions below are detected 500 times or more
continuously. (2 trip detection logic)*
Diagnostic Trouble Code Detection ConditionDTC No.Trouble Area
No. No. 1 vehicle speed sensor signal in 16
pulses of No. 2 vehicle speed sensor signal.
Vehicle speed: 9 km/h (5.6 mph) or more for 4
secs. or more for 4 secs. or more.
Park/neutral position switch:
OFF (Other than P or N position)
42
No. 1 vehicle speed sensor
Telltale light RH
Harness or connector between No. 1 vehicle
speed sensor and ECM
ECM
HINT: In test more, diagnostic trouble code 42 is output when vehicle speed is 5 km/h (3 mph) or
below.
See page AT1±54
< Reference >
HINT: As the vehicle's speed increases, the signal output from
SP1 increases.
Waveform between terminals SP1 and E2 when vehicle speed is approx. 20 km/h (12 mph).
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTINGAT1±66

INSPECTION PROCEDURE
Shift the shift lever to N position.
Jack up one of the rear wheels.
Connect the Check Harness A
(See page EG±404)
Disconnect power steering ECU connector
and cruise control ECU connector.
Turn ignition switch ON.
Measure voltage between terminal SP1 of ECM
connector and body ground when the wheel is
turned slowly.
Check voltage between terminal SP1 of ECM connector and body ground.
Voltage is generated intermittently.
Check and replace ECM.
Repair or replace harness or connector be-
tween ECM and telltale light RH.
Check operation of odometer and trip meter (telltale light RH (See page
BR±48))
AT1±67± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTING

Replace No. 1 vehicle speed sensor.
Repair or replace harness or connector between tell-
tale light RH and No. 1 vehicle speed sensor.
Check operation of No. 1 vehicle speed sensor (See page BR±46).
AT1±68± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTING

DTC 61 No. 2 Vehicle Speed Sensor Circuit
CIRCUIT DESCRIPTION
The No. 2 vehicle speed sensor detects the rotation speed of the transmission output shaft and sends
signals to the ECM. The ECM determines the vehicle speed based on these signals. An AC voltage
is generated in the No.2 vehicle speed sensor coil as the rotor mounted on the output shaft rotates,
and this voltage is sent to the ECM.
The gear shift point and lock±up timing are controlled by the ECM based on the signals from this vehicle
speed sensor and the throttle position sensor signal.
If the No.2 vehicle speed sensor malfunctions, the ECM uses input signals from the No.1 vehicle speed
sensor as a back±up signal.
See page AT1±54
All conditions below are detected 500 times or more
continuously. (2 trip detection logic)*
Diagnostic Trouble Code Detection ConditionDTC No.Trouble Area
No. No. 2 vehicle speed sensor signal in 4
pulses of No. 2 vehicle speed sensor signal.
Vehicle speed: 9 km/h (5.6 mph) or more for 4
secs. or more for 4 secs. or more.
Park/neutral position switch:
OFF (Other than P or N position)
61
No. 2 vehicle speed sensor
Harness or connector between No. 2 vehicle
speed sensor and ECM
ECM
< Reference >Waveform between terminals SP2± and SP2± when vehicle
speed is approx. 60 km/h (37 mph).
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTINGAT1±69

WIRING DIAGRAM
INSPECTION PROCEDURE
Connect the Check Harness A to the ECM (See
page EG±404).
Check resistance between terminals SP2+ and
SP2
- of ECM connector.
Resistance: 560 ± 680

Proceed to next circuit inspection shown on
matrix chart (See page AT1±58).
Check resistance between terminals SP2+ and SP2± of ECM connector.
AT1±70± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTING

Remove No. 2 vehicle speed sensor from trans-
mission (See page AT1±14).
Measure resistance between terminals 1 and 2 of
No. 2 vehicle speed sensor.
Resistance: 560 ± 680

Voltage is generated intermittently.
Check No. 2 vehicle speed sensor.
Check voltage between terminals 1 and 2 of the
speed sensor when a magnet is put close to the
front end of the vehicle speed sensor then taken
away quickly.
The voltages generated is extremely low.
Replace No. 2 vehicle speed sensor.
Check and repair harness and connector between ECM
and No. 2 vehicle speed sensor (See page IN±30).

Check the vehicle speed sensor's function
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTINGAT1±71

DTC 62 63 No.1 No. 2 Solenoid Valve Circuit
CIRCUIT DESCRIPTION
Shifting from 1st to O/D is done in combination with ON and OFF of the No.1 and No.2 solenoid valves controlled
by ECM. If an open or short circuit occurs in either of the solenoid valves, the ECM controls the remaining normal
solenoid to allow the vehicle to be operated smoothly (Fail safe function).
Fail Safe Function
If either of the solenoid valve circuits develops a short or an open, the ECM turns the other solenoid ON and
OFF to shift to the gear positions shown in the table below. The ECM also turns the lock±up solenoid valve OFF
at the same time. If both solenoids malfunction, hydraulic control cannot be performed electronically and must
be done manually.
Manual shifting as shown in the following table must be done (In the case of a short circuit, the ECM stops send-
ing current to the short circuited solenoid).
 
 
Position
 
 NORMAL
 
 NO.1 SOLENOID
MALFUNCTIONING 
 NO.2 SOLENOID
MALFUNCTIONING 
 BOTH SOLENOIDS
MALFUNCTIONING
 
 
Position 
 Solenoid valve 
 Gear
 
 Solenoid valve 
 Gear
 
 Solenoid valve 
 Gear
 
 Gear when shift
selector is manually
  No.1 No.2 Gear No.1 No.2 Gear No.1 No.2 Gear 
selector is manually
operated
  ON OFF 1st X ON 3rd ON X 1st O/D
 D ON ON 2nd X ON 3rd OFF X O/D O/D
  OFF ON 3rd X ON 3rd OFF X O/D O/D
  OFF OFF O/D X OFF O/D OFF X O/D O/D
  ON OFF 1st X ON 3rd ON X 1st 3rd
 2 ON ON 2nd X ON 3rd OFF X 3rd 3rd
  OFF ON 3rd X ON 3rd OFF X 3rd 3rd
 
L
 ON OFF 1st X OFF 1st ON X 1st 1st
 L ON ON 2nd X ON 2nd ON X 1st 1st
X: Malfunctions
Check the No.1 solenoid when diagnostic trouble code 62 is output and check and No.2 solenoid when
diagnostic trouble code 63 is output.
 DTC No. Diagnostic Trouble Code Detection Condition Trouble Area 
 
 
 
 
 
 
 
 
 
 
 
 
 
62, 63
 
 
 
 
 
 
 
 
 
 
 
 
 
 
(a) Solenoid resistance is 8
or lower (short cir±
cuit) when solenoid is energized.
(b) Solenoid resistance is 100 k
or higher (open
circuit) when solenoid is not energized.
The ECM checks for an open or short circuit in the
No.1 and No.2 solenoid circuit when it changes
gear position.
The ECM records diag. trouble code 62 or 63 if
condition (a) or (b) is detected once, but it does
not blink the O/D OFF indicator light.
After the ECM detects the condition (a) or (b)
continuously 8 times or more in one±trip *, it
causes the O/D OFF indicator light to blink until
condition (a) or (b) disappears.
After that, if the ECM detects condition (a) or
(b) one, it starts blinking the O/D OFF indicator
light again. 
 
 
 
 
 
 
 
 
 
 
 
 
 

Solenoid valve

Harness or connector between solenoid and

ECM

ECM
* one±trip (1st trip) See page AT1±54 AT1±72
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTING

WIRING DIAGRAM
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTINGAT1±73

Jack up the vehicle.
Remove the oil pan.
Disconnect the solenoid connector.
Measure resistance between solenoid connector
and solenoid body.
Resistance: 10 ± 16

Connect positive (+) lead to terminal of solenoid
connector, negative (±) lead to solenoid body.
Check No. 1, No. 2 solenoid valves.
When battery positive voltage is supplied to
the solenoid valves, check that the solenoid
valves open.
Replace solenoid valve.
Electrical Check
Repair or replace harness or connector.
Check harness and connector between ECM and solenoid (See page IN±30).
Proceed to next circuit inspection shown on matrix chart
(See page AT1±58). However, when diagnostic trouble
code 62 or 63 is displayed, check and replace ECM.
Applying 490 kPa (5 kgf/cm2, 71 psi) of com-
pressed air, check that the solenoid valves do
not leak air.
Remove the oil pan.
Remove the No. 1 and No. 2 solenoid valves.
The solenoid makes an operating noise.
Mechanical Check
INSPECTION PROCEDURE
AT1±74± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTING