1991 LEXUS SC300 fuse diagram

OK
Check operation of airbag warning light.
NG1
WIRING DIAGRAM
2Is diagnostic code 41 output again? System is normal.
Check harness between ECU±B
fuse and center airbag sensor as-
sembly. If normal, replace center
airbag sensor assembly.
Perform troubleshooting according to
malfunction code output. NO
YES
Diag. Code 41Malfunction Stored in Memory
CIRCUIT DESCRIPTION
If a malfunction occurs in the airbag system, malfunction codes 11 to 31 may be output, and when the
battery is disconnected after the malfunction is repaired, malfunction codes 11 to 31 will be cleared,
but code 41 will be output instead.
So long as the cancellation operation for a malfunction stored in memory (\
See page
AB±32) is not per-
formed, code 41 is stored in the center airbag sensor assembly and the airbag w\
arning light remains
lit up.
Code No.Diagnosis
41
Malfunction recorded in memory.41
Center airbag sensor assembly malfunction.
DIAGNOSTIC CHART
AB±82±
SRS AIRBAG Troubleshooting
WhereEverybodyKnowsYourName

Wiring Diagram
CENTER AIRBAG SENSOR ASSEMBLY CONNECTOR
No.SymbolTerminal NameNo.SymbolTerminal Name
18E2Ground
2±SRRH Front Airbag Sensor (±)9LAAirbag Warning Light
3+SRRH Front Airbag Sensor (+)10D±Squib (±)
4+SLLH Front Airbag Sensor (+)11D+Squib (+)
5±SLLH Front Airbag Sensor (±)12TcDiagnosis
6+BBattery (ECU±B Fuse)13E1Ground
7IG2Power Source (IGN Fuse)14AccPower Source (CIG Fuse)
AL1Electrical Connection Check
MechanismBL2Electrical Connection Check
Mechanism
AB±33SRS AIRBAG ± Troubleshooting
WhereEverybodyKnowsYourName

(b) Press the mirror switch and check if the mirrors surfacerepeatedly becomes ºbrightº and ºdarkº.
If operation is not as specified, replace the liquid crystal inner
mirror.
(Circuit)
Disconnect the inner mirror connector and inspect the con-
nector on the wire harness side as shown.
Check forTester connectionConditionSpecified value
Voltage2±GroundConstantBattery voltage
Continuity1 GroundIgnition key setContinuityContinuity1±GroundIgnition key removedNo continuity
If circuit is not as specified, refer to BE±165 wiring diagram
and inspect the circuits connected to other parts.
(Key Unlock Warning Switch)
(See page BE±26)
Troubleshooting
You will find the cause of trouble more easily by properly using the table \
shown below. In this table, the numbers
indicate the order of priority of the cruses of trouble. Check each part in the \
order shown. If necessary, replace
the part.
See pageBE±4,21BE±165BE±26 ±±
TroubleParts
name
DOME FuseLiquid Crystal Inner MirrorKey Unlock Warning SwitchWire Harness
Liquid Crystal Inner Mirror does not operate.1234
BE±166±
BODY ELECTRICAL SYSTEM Liquid Crystal Inner Mirror System
WhereEverybodyKnowsYourName

CIRCUIT INSPECTION
+B Power Source Circuit
CIRCUIT DESCRIPTION
This is the power source for motors such as the slide motor and reclining mo\
tor.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
Check Door fuse.NG
Check for short in all harness and
components connected to the
DOOR fuse (See attached wiring
diagram).
Check voltage between terminals +B, +B2
and GND of ECU connector. OK
OKProceed to next circuit inspection
shown on matrix chart (See page
BE±276
).
Check continuity between terminal GND
of ECU connector and body ground. NG
NGRepair or replace harness or
connector.
OK
Check and repair harness or connector
between ECU and battery.
WIRING DIAGRAM
BE±284±
BODY ELECTRICAL SYSTEM Power Seat Control System (Driver's Seat)
WhereEverybodyKnowsYourName

OKNG
NGOK
OKNG
INSPECTION PROCEDURE
1Check DOOR fuse.
Check for short in all the harness and components con-
nected to the DOOR fuse (See attached wiring diagram).
2Check voltage between terminals +B, +B2 and GND of ECU connector.
C
OK
PRemove ECU with connectors still connected.
Measure voltage between terminals +B, +B2 and GND
of ECU connector.
Voltage: 10 ± 14 V
Proceed to next circuit inspection shown on matrix chart
(See page BE±276.)
3Check continuity between terminal GND of ECU connector and body ground.
C
OK
Measure resistance between terminal GND of ECU and
body ground.
Resistance: 1
or less.
Repair or replace harness or connector.
Check and repair harness or connector between
ECU and battery.
±
BODY ELECTRICAL SYSTEM Power Seat Control System (Driver's Seat)BE±285
WhereEverybodyKnowsYourName

WIRING DIAGRAM
ECU Power Source Circuit
CIRCUIT DESCRIPTION
This circuit provides power for ECU operation and is also the power source f\
or the sensors.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
Check DOME fuse.NGCheck for short in all the harness
and components connected to
DOME fuse.
(See attached wiring diagram).
OK
Check voltage between terminals SYSB
and SGND of ECU connector. Proceed to next circuit inspection
shown on matrix chart
(See page
BE±276).
Check continuity between terminal SGND
of ECU connector and body ground. OK
NG
OK NG
Replace or repair harness or
connector.
Check and repair harness or connector
between ECU and battery.
BE±286±
BODY ELECTRICAL SYSTEM Power Seat Control System (Driver's Seat)
WhereEverybodyKnowsYourName

OKNG
NGOK
OKNG
INSPECTION PROCEDURE
1Check DOME fuse.
Check for short in all the harness and components con-
nected to the DOME fuse (See attached wiring diagram).
2Check voltage between terminals SYSB and SGND of ECU connector.
C
OK
PRemove ECU with connectors still connected.
Measure voltage between terminals SYSB and SGND
of ECU connector.
Voltage: 10 ± 14 V
Proceed to next circuit inspection shown on matrix chart
(See page BE±276).
3Check continuity between terminal SGND of ECU connector and body ground.\
C
OK
Measure resistance between terminal SGND of ECU
connector and body ground.
Resistance: 1
or less.
Repair or replace harness or connector.
Check and repair harness or connector between
ECU and battery.
±
BODY ELECTRICAL SYSTEM Power Seat Control System (Driver's Seat)BE±287
WhereEverybodyKnowsYourName

WIRING DIAGRAM
Ignition Switch Circuit
CIRCUIT DESCRIPTION
This circuit sends an ignition switch ON or OFF signal to the ECU.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
Check ECU±IG fuse.NG
Check for short in all the harness
and components connected to
ECU±IG fuse.
Check voltage between terminal IG of
ECU connector and body ground. OK
OK
NG Proceed to next circuit inspection
shown on matrix chart
(See page
BE±276).
Check and repair harness or connector
between ECU and battery (See page IN±27).
BE±302±
BODY ELECTRICAL SYSTEM Power Seat Control System (Driver's Seat)
WhereEverybodyKnowsYourName