ect LEXUS SC300 1991 Service Repair Manual

OKNG
OKNG
OKNG
INSPECTION PROCEDURE
1Check voltage between terminal R, PNP, 2, L of ECM connector and body ground.
C
OK
P1. Connect the check harness A to the ECM (See EGsection).
2. Turn ignition switch ON.
Measure voltage between terminals R, PNP, 2, L of
ECM connector and body ground when the shift lever is
moved to the following positions.
*: The voltage will drop slightly due to lighting up of the
back up light.
Proceed to next circuit inspection shown on matrix chart
(See page AT±66).
2Check park/neutral position switch.
C
P1. Jack up the vehicle.
2. Remove park/neutral position switch (See page AT±18).
Check continuity between each terminal shown below
when the shift lever is moved to each position.
Replace park/neutral position switch.
3Check harness and connector between ECM and park/neutral position switch, park\
/neutral
position switch and battery (See page IN±33).
Repair or replace harness and connector.
Check and replace ECM.
±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTINGAT±107
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OKNG
OKNG
OKNG
INSPECTION PROCEDURE
1Check operation of stop light.
Check if the stop lights go on and off normally when the brake pedal is operated and released.C
Check and repair stop light circuit (See BE section).
2Check stop light signal.
C
OK
1. Connect voltmeter to the terminals TT and E1 of the
DLC2.
2. Turn ignition switch ON (Do not start the engine).
3. Fully depress the accelerator pedal until the volt- meter indicates 8 V and hold it.
4. Depress and release the brake pedal and check the
voltage.
Proceed to next circuit inspection shown on matrix chart
(See page AT±66).
3Check harness and connector between ECM and stop light switch (See page\
IN±33).
Repair or replace harness or connector.
Check and replace ECM.
±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTINGAT±109
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AT±66
IN±33
WIRING DIAGRAM
Pattern Select Switch Circuit
CIRCUIT DESCRIPTION
The ECM memory contains the shift programs for the NORMAL and POWER pattern\
s, 2 position and L
position 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 sensor\
s the ECM switches the solenoid
valves ON and OFF, thereby controlling the transmission gear change and the lock±up cl\
utch operation.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
AT±110±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTING
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OKNG
OKNG
OKNG
INSPECTION PROCEDURE
1Check voltage between terminal P of ECM connector and body ground.
C
OK
Hint
P1. Connect the check harness A to the ECM (See EGsection).
2. Turn ignition switch ON.
Measure voltage between terminal P of ECM connector
and body ground when the pattern select switch is set
to the PWR (POWER) position and NORM (NORMAL)
position.
The ECM uses the normal pattern signal if the power
signal is not input.
Proceed to next circuit inspection shown on matrix chart
(See page AT±66).
2Check pattern select switch.
C
OK
PDisconnect pattern select switch connector. (See BO
section).
Measure resistance between terminals 1 and 2 of pat-
tern select switch connector when the select switch is
set to PWR and NORM positions.
Replace pattern select switch.
3Check harness and connector between ECM and pattern select switch, patte\
rn select switch
and battery (See page IN±33).
Repair or replace harness or connector.
Check and replace ECM.
±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTINGAT±111
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WIRING DIAGRAM
O/D Main Switch and O/D OFF Indicator Light Circuit
CIRCUIT DESCRIPTION
The O/D main switch contacts go off when the switch is pushed in and comes on when it is pushed out.
In O/D main switch OFF position, the O/D OFF indicator lights up, and the \
ECM prohibits shifting to over-
drive. The ECM also causes the O/D OFF indicator light to blink when a malfunc\
tion is detected. In this
case, connecting the terminals in the DLC2 or DLC1 can display the malfu\
nction code.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
See next page.
AT±112
±
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OKNG
OKNG
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INSPECTION PROCEDURE
1Check operation of O/D Main Switch
C
OK
Hint
C
OK
1. Turn ignition switch ON.
2. Check ªO/D OFFº light when O/D main switch ispushed in to ON.
ªO/D OFFº light goes off.
3. Check ªO/D OFFº light when O/D main switch is pushed again, to OFF.
ªO/D OFFº light lights up.
If the ªO/D OFFº lights blinks when the O/D main switch
is pushed in to ON, a malfunction is occurring in the sys-
tem.
Check the diagnostic trouble code.
Go to step
.
2Check voltage between terminal OD2 of ECM connector and body ground.
C
OK
P1. Connect the check harness A to the ECM (See EG
section).
2. Turn ignition switch ON.
Check voltage between terminal OD2 of ECM and body
ground
Proceed to next circuit inspection shown on matrix chart
(See page AT±66).
3Check harness and connector between O/D off indicator light and ECM (Se\
e page IN±33).
Repair or replace harness or connector.
Check and replace ECM.
AT±114±
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OKNG
4Check O/D Main Switch.
C
OK
1. Disconnect O/D main switch connector. (See BOsection).
2. Measure resistance between terminals 2 and 4 of O/D main switch connector.
Replace O/D Main Switch.
Check and replace combination meter. (See com-
bination meter troubleshooting on BE section).
±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTINGAT±115
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AT±66
IN±33
WIRING DIAGRAM
O/D Cancel Signal Circuit
CIRCUIT DESCRIPTION
While driving with cruise control activated, in order to minimize gear shifti\
ng and provide smooth cruising
when driving uphill, 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 s\
hifting until these signals
are discontinued.(For details, see the cruise control system, on BE sectio\
n).
DIAGNOSTIC CHARTDIAGNOSTIC CHART
AT±116±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTING
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NGOK
NGOK
OKNG
INSPECTION PROCEDURE
1Check voltage between terminal OD1of ECM connector and body ground.
C
OK
P1. Connect the check harness A to the ECM (See EGsection).
2. Turn ignition switch ON.
Measure voltage between terminal OD1 of ECM con-
nector and body ground.
Voltage: 4 ± 6 V
Proceed to next circuit inspection shown on matrix chart
(See page AT±66).
2Check voltage between terminal OD of cruise control ECU harness side con\
nector and body
ground.
C
OK
P1. Disconnect cruise control ECU connector.
2. Turn ignition switch ON.
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.
3Check harness or connector between cruise control ECU and ECM (See page\
IN±33).
Repair or replace harness or connector.
Check and replace ECM.
±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTINGAT±117
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AT±66
IN±33
WIRING DIAGRAM
TE1 Terminal Circuit
CIRCUIT DESCRIPTION
ECM displays diagnostic trouble codes using the O/D OFF indicator light \
when terminals TE and E of the
DLC2 or DLC1 are connected.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
AT±118±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTING
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