code 32 LEXUS SC300 1991 Service Repair Manual

DIAGNOSTIC CHART
DIAGNOSTIC
CHART
Troubleshooting for this system is different for when the SRS warning light does not light up and for when dia\
g-
nostic trouble code 22 is output. Confirm the problem symptoms first before selecting the appropriate trouble-
shooting procedure.
HINT: If SRS warning light does not light up, perform the following troubles\
hooting:
(See page RS±65)
±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTINGRS±103
WhereEverybodyKnowsYourName

WIRING DIAGRAM
DIAGNOSTIC CHARTDIAGNOSTIC CHART
HINT: If diagnostic trouble code 22 is output, perform the following troubles\
hooting:
(See page RS±65).
RS±104±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTING
WhereEverybodyKnowsYourName

YESNo
HINT: If diagnostic trouble code 22 is output, perform the following troubles\
hooting:
1Is diagnostic trouble code 22 output again?
C
PClear malfunction.
1. Turn ignition switch LOCK, and wait at least 20 sec-onds.
2. Turn ignition switch ACC or ON, and wait at least 20 seconds.
3. Using SST, connect terminals Tc and E
1 of DLC2.
SST 09843±18020
4. Check diagnostic trouble code.
Using simulation method, reproduce malfunction symp-
toms (See page RS±65).
Replace center airbag sensor assembly.
±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTINGRS±107
WhereEverybodyKnowsYourName

DTC31Center Airbag Sensor Assembly Malfunction
CIRCUIT DESCRIPTION
The center airbag sensor assembly consists of center airbag sensor, safing sensors, ignition control and drive
circuit, diagnosis circuit, etc.
It receives signals from the airbag sensors, judges whether or not the SRS must be deploy, and diagnoses sys-
tem malfunction.
Diagnostic trouble code 31 is recorded when occurrence of a malfunction in the cen\
ter airbag assembly is de-
tected.
DTC No.Trouble Area
31
Center airbag sensor assembly malfunction.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
HINT: When a malfunction code other than code 31 is displayed at the same time, first repair the malfunction
indicated by the malfunction code other than code 31.
(See page RS±65).
RS±108±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTING
WhereEverybodyKnowsYourName

YESNO
INSPECTION PROCEDURE
HINT: When a malfunction code other than code 31 is displayed at the same time, first repair the malfunction
indicated by the malfunction code other than 31.
1Is diagnostic rouble code 31 output again?
C
PClear malfunction.
1. Turn ignition switch LOCK, and wait at least 20 sec-onds.
2. Turn ignition switch ACC or ON, and wait at least 20 seconds.
3. Repeat operation in step (1) and (2) at least 5 times.
4. Using SST, connect terminals Tc and E
1 of DLC2.
SST 09843±18020
5. Check diagnostic trouble code.
Using simulation method, reproduce malfunction symp-
toms (See page RS±65).
Replace center airbag sensor assembly.
±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTINGRS±109
WhereEverybodyKnowsYourName

Check EFI fuse.
Check voltage of terminal BATT.
Check operation for the back±up.
Proceed to next circuit inspection
shown on matrix chart (See page TR±39).
Check for short in all the harness and
components connected to EFI fuse.
Check and repair harness or connector
between battery, EFI fuse and ECU.
Check and replace fuse.
WIRING DIAGRAM
Back Up Power Source Circuit
CIRCUIT DESCRIPTION
Battery voltage is supplied to terminal BATT of the ECU even when the ignition switch is off for use
by the diagnostic code memory and air±fuel ratio adaptive control val\
ue memory, etc.
DIAGNOSTIC CHART
TR±126±
ENGINE TROUBLESHOOTING Circuit Inspection
WhereEverybodyKnowsYourName

OKNG
OKNG
YESNO
INSPECTION PROCEDURE
1Check EFI fuse.
C
OK
PRemove EFI fuse from R/B No. 2
Check continuity of EFI fuse.
Continuity
Check for short in all the harness and components
connected to EFI fuse (See attached wiring diagram).
2Check voltage between terminal BATT of engine (& ECT) ECU connector and body ground.
C
OK
PConnect the Check Harness A. (See page TR±34)
Measure voltage between terminal BATT of engine
(& ECT) ECU connector and body ground.
Voltage: 10 ± 14 V
Check and repair harness or connector between engine
(& ECT) ECU and EFI fuse, EFI fuse and battery.
3Are the diagnostic trouble codes still in the memory when the ignition s\
witch is turned OFF?
Check and replace engine (& ECT) ECU.
Proceed to next circuit inspection shown on
matrix chart (See page TR±39).
±
ENGINE TROUBLESHOOTING Circuit InspectionTR±127
WhereEverybodyKnowsYourName

Back Up Power Source Circuit
CIRCUIT DESCRIPTION
Battery voltage is supplied to terminal BATT of the ECU even when the ignition switch is off for use by
the diagnostic code memory and air±fuel ratio adaptive control value mem\
ory, etc.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
Check for short in all the harness and
components connected to EFI fuse.Check EFI fuse.
Check of terminal BATT.
Proceed to next circuit inspection shown on
matrix chart (See page TR±35).
Check operation for the back up.Check and replace ECU.
Check and repair harness or connector
between battery, EFI fuse and ECU.
WIRING DIAGRAM
TR±130±
ENGINE TROUBLESHOOTING Circuit Inspection
WhereEverybodyKnowsYourName

OKNG
OKNG
YESNO
INSPECTION PROCEDURE
1Check EFI fuse.
C
OK
PRemove EFI fuse from R/B No.2.
Check continuity of EFI fuse.
Continuity
Check for short in all the harness and components con-
nected to EFI fuse (See attached wiring diagram).
2Check voltage between terminal BATT of engine & ECT ECU connector and body ground.
C
OK
PConnect the Check Harness A.
(See page TR±30).
Measure voltage between terminal BATT of engine &
ECT ECU connector and body ground.
Voltage: 10 ± 14 V
Check and repair harness or connector between engine
& ECT ECU and EFI fuse, EFI fuse and battery.
3Are the diagnostic codes still in the memory when the ignition switch is\
turned OFF?
Check and replace engine & ECT ECU.
Proceed to next circuit inspection shown on ma-
trix chart (See page TR±35).
±
ENGINE TROUBLESHOOTING Circuit InspectionTR±131
WhereEverybodyKnowsYourName

TE1, TE2 Terminal Circuit
CIRCUIT DESCRIPTION
Terminal TE1 is located in the check connector in the engine compartment and terminals T\
E1 and TE2 are lo-
cated in the TDCL in the cabin. When these terminals are connected with \
the E1 terminal, diagnostic codes in
normal mode or test mode can be read from the ºCHECKº engine warning lig\
ht on the combination meter.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
HINT: If terminals TE1 and TE2 are connected with terminal E1, diagnostic code is not output or test mode isnot activated.
Even though terminal TE1 is not connected with terminal E1, the ºCHEC\
Kº engine warning light blinks.
For the above phenomenon, the likely cause is an open or short in the wire \
harness, or malfunction inside
the ECU.
Check continuity between terminal E1 and
body ground.
Repair or replace harness or
connector.Check for open and short in harness and
connector between check connector TDCL
and ECU.
Check voltage of terminals TE1, TE2.
Check and replace ECU.
Repair or replace harness or
connector.
Check and replace ECU.
WIRING DIAGRAM
TR±146±
ENGINE TROUBLESHOOTING
WhereEverybodyKnowsYourName