TOYOTA SUPRA 1995 Service Repair Manual

Pattern Select Switch Circuit
CIRCUIT DESCRIPTION
The ECM memory contains the shift programs for the NORMAL and MANUAL patterns, 2 position, and L posi-
tion and the lock±up patterns. Following the programs corresponding to the signals from the pattern select
switch, the park/neutral position switch and other various sensors the ECM switches the solenoid valves ON
and OFF, thereby controlling the transmission gear change and the lock±up clutch operation.
WIRING DIAGRAM
INSPECTION PROCEDURE
Check A/T fluid temp. sensor. (See page AT1±64).
Replace A/T fluid temp. sensor.
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTINGAT1±85

Turn ignition siwtch ON.
Check ªMANUº mode indicator light when pat-
tern select switch is pushed in to ON.
Check if A/T fluid is too hot.
Pattern select switch
Connect the Check Harness A to the ECM
(See page EG±404).
Turn igntion switcn ON.
Check voltage between terminal M of ECM connector and body ground.
Proceed to next circuit inspection shown on
matrix chart. (See page AT1±58)
Voltage
MANU7.5 ± 14 V
NORMBelow 1.5 V
Wait until the A/T fluid temp. is reduced.
The ECM uses the Normal pattern signal if the
Manual signal is not input.
Measure voltage between the terminal M of ECM
connector and body ground when the pattern se-
lect switch is set to the MANU (MANUAL) position
and NORM (NORMAL) position.
ºMANUº mode indicator light comes on and stays
on.
If the A/T fluid temp. becomes too hot, the
ªMANUº mode indicator light flashes for several
seconds and goes off. The driving mode then
automatically changes from MANU mode to the
NORM mode. AT1±86
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTING

Pattern
Disconnect the pattern select switch connector.
Check pattern select switch.
Repair or replace harness or connector.
Resistance
MANU0
(continuity)
NORM
Check and replace ECM.
Measure resistance between terminals 3 and 4 of
the pattern select switch connector when the select
switch is set to the MANU and NORM positions.
8
(open)
Replace pattern select switch.
Check harness and connector between battery and pattern select switch,
pattern select switch and ECM (See page IN±30).
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTINGAT1±87

O D Main Switch & O D OFF Indicator Light Circuit
CIRCUIT DESCRIPTION
The O/D main switch contacts go off when the switch is pushed in and come on when it is pushed out. In O/D
main switch OFF position, the O/D OFF indicator light lights up, and the ECM prohibits shifting to overdrive. The
ECM also causes the O/D OFF indicator light to blink when a malfunction is detected. In this case, connecting
the terminals in the DLC2 or DLC1 can display the malfunction code.
WIRING DIAGRAM
AT1±88± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTING

INSPECTION PROCEDURE
O/D OFF indicator light does not light up.
Turn ignition switch ON.
Check ªO/D OFFº indicator light when O/D
main switch is pushed in to ON.
Check operation of O/D main switch.
Connect the Check Harness A to the ECM
(See page EG±404).
Turn ignition switch ON.
ºO/D OFFº indicator light goes off.
If the ªO/D OFFº indicator light blinks when the
O/D main switch is pushed in to ON, a malfunc-
tion is occurring in the system.
Check the diagnostic trouble code.
Check voltage between terminal OD2 of ECM connector and body ground.
ºO/D OFFº indicator light lights up.
Check ªO/D OFFº indicator light when O/D main
switch is pushed again, to OFF.
Check voltage between terminal OD2 of the ECM
and body ground.
O/D Main SwitchVoltage
OFFBelow 3 V
ON9 ± 14 V
Proceed to next circuit inspection shown on
matrix chart (See page AT1±58).
Repair or replace harness or connector.
Check and replace ECM.
Check harness and connecter between O/D off indicator light and ECM
(See page IN±30).
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTINGAT1±89

Disconnect the O/D main switch connector.
Measure resistance between terminals 2 and 4
of O/D main switch connector.
Check O/D main switch.
O/D Main SwitchResistance
ON
0
(continuity)OFF
8
(open)
Replace O/D main switch.
Check and replace combination meter.
(See combination meter troubleshooting section on
page BE±41).
Replace O/D main switch.
Check O/D main switch.
Check harness and connector between O/D off indicator light and ECM
(See page IN±30).
Repair or replace harness or connector.
Check and replace ECM.
O/D OFF indicator light remains ON
O/D OFF indicator light blinks
Do diagnostic trouble code check (See page AT1±52). AT1±90
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTING

O D Cancel Signal Circuit
CIRCUIT DESCRIPTION
While driving with cruise control activated, in order to minimize gear shifting and provide smooth uphill cruising,
overdrive may be prohibited temporarily in some conditions.
The Cruise Control ECU sends O/D cut signals to the ECM as necessary and the ECM cancels overdrive shifting
until these signals are discontinued.
(For details, see the cruise control section, page BE±162)
WIRING DIAGRAM
INSPECTION PROCEDURE
Connect the Check Harness A to the ECM
(See page EG±404).
Turn ignition switch ON.
Check and replace ECM.
Check voltage between terminal OD1 of ECM connector and body ground.
Measure voltage between terminal OD1 of ECM
connector and body ground.
Proceed to next circuit inspection shown on
matrix chart (See page AT1±58).
Voltage: 4 ± 6 V
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTINGAT1±91

Disconnect Cruise Control ECU connector.
Turn ignition switch ON.
Repair or replace harness or connector.
Check and replace ECM.
Check voltage between terminal OD of Cruise Control ECU harness side
connector and body ground.
Measure voltage between terminal OD of Cruise
Control ECU harness side connector and body
ground.
Voltage 4 ± 6 V
Check and replace Cruise Control ECU.
Check harness and connector between Cruise Control ECU and ECM (See
page IN±30).
AT1±92± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTING

TE1 Terminal Circuit
CIRCUIT DESCRIPTION
ECM displays diagnostic trouble codes using the O/D OFF indicator light when terminals TE1 and E1 of the
DLC2 or DLC1 are connected.
± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTINGAT1±93

INSPECTION PROCEDURE
Repair or replace harness or connector.
Check and replace ECM.
Check voltage between terminal TE1 and E1 of DLC2 or DLC1.
Measure voltage between terminals TE1 and E1
of DLC2 or DLC1.
Voltage 4 ± 6 V
Proceed to next circuit inspection shown on
matrix chart (See page AT1±58).
Check harness and connector between ECM and DLC2, DLC1 and body
ground (See page IN±30).
AT1±94± AT340E (2JZ±GE) AUTOMATIC TRANSMISSIONTROUBLESHOOTING