ignition LEXUS SC300 1991 Service Repair Manual

OKNG
OKNG
5Check P squib circuit.
OK
PFor the connector (on the center airbag sensor assem-
bly side) between the center airbag sensor assembly
and front passenger airbag assembly, measure the re-
sistance between P+, P± and body ground.
Resistance: 1 M
or Higher
Repair or replace harness or connector between the cen-
ter airbag sensor assembly and front passenger airbag
assembly.
6Check center airbag sensor assembly.
C
OK
Hint
P1. Connect connector to center airbag sensor assem- bly.
2. Using a service wire, connect D+ and D± on spiral cable side of connector between spiral cable and
steering wheel pad.
3. Using a service wire, connect P+ and P± on center airbag sensor assembly and front passenger air-
bag assembly.
4. Connect negative (±) terminal cable to battery, and wait at least 2 seconds.
1. Turn ignition switch ACC or ON and wait at least 20 seconds.
2. Using SST, connect terminals Tc and E
1 of DLC2.
SST 09843±18020
3. Check diagnostic trouble code.
Diagnostic trouble code 11 is not output.
Codes other than code 11 may be output at this time, but
this is not relevant to this check.
Replace center airbag sensor assembly.
±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTINGRS±75
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OKNG
OKNG
7Check D squib.
C
OK
Hint
P1. Turn ignition switch LOCK.
2. Disconnect battery negative (±) terminal cable, andwait at least 90 seconds.
3. Connect steering wheel pad (squib) connector.
4. Connect negative (±) terminal cable to battery, and wait at least 2 seconds.
1. Turn ignition switch ACC or ON, and wait at least 20
seconds.
Clear malfunction code. Turn ignition switch LOCK
and wait at least 20 seconds.
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.
Diagnostic trouble code 11 is not output.
Codes other than code 11 may be output at this time, but
this is not relevant to this check.
Replace steering wheel pad.
8Check P squib.
C
OK
Hint
P1. Turn ignition switch LOCK.
2. Disconnect battery negative (±) terminal cable, and
wait at least 20 seconds.
3. Connect front passenger airbag assembly (squib) connector.
4. Disconnect steering wheel pad (squib) connector.
5. Connect negative (±) terminal cable to battery and wait at least 2 seconds.
1. Turn ignition switch ACC or ON, and wait at least 20
seconds.
Clear malfunction code. Turn ignition switch LOCK
and wait at least 20 seconds.
2. Turn ignition switch ACC or ON, and wait at least 20
seconds.
3. Using SST, connect terminals Tc and E
1 of DLC2.
4. Check diagnostic trouble code.
Diagnostic trouble code 11 is not output.
Codes other than code 11 nay be output at this time, but
they are not relevant to this check.
Replace front passenger airbag assembly.
RS±76
±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTING
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OKNG
OKNG
3Check front airbag sensor circuit. (Measure voltage between terminals +SR or\
+SL of center
airbag sensor assembly connector and body ground.)
C
OK
P1. Connect negative (±) terminal cable to battery.
2. Turn ignition switch ON.
Measure voltage between terminals +SR or +SL of har-
ness side connector of center airbag sensor assembly
and body ground.
Voltage: Below 1 V
Repair or replace harness or connector between center
airbag sensor assembly and front airbag sensor (See
page RS±48 ).
4Check D squib circuit.
C
OK
PDisconnect center airbag sensor assembly connector.
Measure resistance voltage between D+ and D± on spi-
ral cable side of connector between spiral cable and
steering wheel pad.
Voltage: Below 1 V
Go to step 
±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTINGRS±81
WhereEverybodyKnowsYourName

OKNG
OKNG
5Check P squib circuit.
C
OK
Measure voltage at P+ on spiral cable side of connector
between spiral cable and steering wheel pad.
Voltage: Below 1 V
Go to step

6Check center airbag sensor assembly.
C
OK
Hint
P1. Turn ignition switch LOCK.
2. Disconnect negative (±) terminal cable from bat-
tery.
3. Connect connector to center airbag sensor assem- bly.
4. Using a service wire, connect D
+ and D± on spiral
cable side connector between spiral cable and
steering wheel pad.
5. Using a service wire, connect P
+ and P± on center
airbag sensor assembly side of connector between
center airbag sensor assembly a dn front passen-
ger airbag assembly.
6. Connect negative (±) terminal cable to battery, and wait at least 2 seconds.
1. Turn ignition switch ACC or ON and wait at least 20 seconds.
Clear malfunction code. Turn ignition switch LOCK
and wait at least 20 seconds.
2. Turn ignition switch ACC or ON, an s wait at least 20 seconds.
3. Using SST, connect terminals Tc and E
1 of DLC2
SST 09843±18020
4. Check diagnostic trouble code.
Diagnostic trouble code 12 is not output.
Code other than code 12 may be output at this time, but
this is not relevant to this check.
Replace center airbag sensor assembly.
RS±82
±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTING
WhereEverybodyKnowsYourName

OKNG
OKNG
7Check D squib.
C
OK
Hint
P1. Turn ignition switch LOCK.
2. Disconnect battery negative (±) terminal cable, andwait at least 90 seconds.
3. Connect steering wheel pad (squib) connector.
4. Connect negative (±) terminal cable to battery, and wait at least 2 seconds.
1. Turn ignition switch ACC or ON and wait at least 20 seconds.
Clear malfunction code. Turn ignition switch LOCK
and wait at least 20 seconds.
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.
Diagnostic trouble code 12 is not output.
Codes other t han code 12 may be output at this time, but
is not relevant to this check.
Replace steering wheel pad.
8Check P squib.
C
OK
Hint
P1. Turn ignition switch LOCK.
2. Disconnect battery negative (±) terminal cable, and
wait at least 90 seconds.
3. Connect front passenger airbag assembly (squib) connector.
4. Disconnect steering wheel pad (squib) connector.
5. Connect negative (±) terminal cable to battery, and wait at least 2 seconds.
1. Turn ignition switch ACC or ON and wait at least 20 seconds.
Clear malfunction code. Turn ignition switch LOCK
and wait at least 20 seconds.
2. Turn ignition switch ACC or ON, and wait at least 20
seconds.
3. Using SST, connect terminals Tc and E
1 of DLC2.
4. Check diagnostic trouble code.
Diagnostic trouble code 12 is not output.
Codes other t han code 12 may be output at this time, but
they are not relevant to this check.
Replace center airbag sensor assembly.
±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTINGRS±83
WhereEverybodyKnowsYourName

OKNG
From the results of the above inspection, the malfunctioning part can now be\
considered normal. To
make sure of this, use the simulation method to check.
9Check spiral cable.
C
OK
P1. Turn ignition switch LOCK.
2. Disconnect connector between center airbag sen-sor assembly and spiral cable.
3. Turn ignition switch ON.
Measure voltage at D+ on spiral cable side of connector
between spiral cable and steering wheel pad.
Voltage: Below 1 V
Repair or replace spiral cable.
Repair or replace harness or connector between center airbag sensor asse\
mbly and spiral cable.
RS±84±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTING
WhereEverybodyKnowsYourName

OKNG
OKNG
3Check center airbag sensor assembly.
C
OK
Hint
P1. Using a service wire, connect D+ and D±.
2. Using a service wire, connect P
+ and P±.
3. Connect negative (±) terminal cable to battery.
4. Clear malfunction.
5. Turn ignition switch LOCK, and wait at least 20 sec- onds.
6. Disconnect service wire of D
+ and D±.
7. Turn ignition switch ACC or ON, and wait at least 20
seconds.
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 09842±18020
4. Check diagnostic trouble code.
Diagnostic trouble code 13 is not output.
Codes other t han code 13 may be output at this time, but
this is not relevant to this check.
Replace center airbag sensor assembly.
4Check D squib.
C
OK
Hint
P1. Turn ignition switch LOCK.
2. Disconnect battery negative (±) terminal cable, and wait at least 90 seconds.
3. Connect steering wheel pad (squib) connector.
4. Connect negative (±) terminal cable to battery.
5. Clear 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.
Diagnostic trouble code 13 is not output.
Codes other t han code 13 may be output at this time, but
this is not relevant to this check.
Replace steering wheel pad.
RS±88
±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTING
WhereEverybodyKnowsYourName

OKNG
OKNG
5Check center airbag sensor assembly.
C
OK
Hint
P1. Connect connector to center airbag sensor connec-
tor.
2. Connect connector between center airbag sensor assembly and spiral cable.
3. Using a service, wire, connect D
+ and D±. P+ and
P±.
4. Connect negative (±) terminal cable to battery and wait at least 2 second.
1. turn ignition switch ACC or ON, and wait at least 20
seconds.
Clear malfunction code. Turn ignition switch LOCK
and wait at least 20 seconds.
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.
Diagnostic trouble code 14 is not output.
Codes other than code 14 may be output at this time ,
but this is not relevant to this check.
Replace center airbag sensor assembly.
6Check D squib.
C
OK
Hint
P1. Turn ignition switch LOCK.
2. Disconnect battery negative (±) terminal cable, and wait at least 90 seconds.
3. Connect steering wheel pad (squib) connector.
4. Connect negative (±) terminal cable to battery, and wait at least 2 seconds.
1. Turn ignition switch ACC or ON, and wait at least 20
seconds.
Clear malfunction code. Turn ignition switch LOCK
and wait at least 20 seconds.
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.
Diagnostic trouble code 14 is not output.
Codes other t han code 14 may be output at this time, but
this is not relevant to this check.
Replace steering wheel pad.
From the results of the above inspection, the malfunctioning part can now be\
considered normal. To
make sure of this, use the simulation method to check.
RS±96±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTING
WhereEverybodyKnowsYourName

OKNG
3Check center airbag sensor assembly.
C
OK
Hint
P1. Connect connector to center airbag sensor assem-bly.
2. Using a service wire, connect D+ and D± on spiral cable side of connector between spiral cable and
steering wheel pad.
3. Using a service wire, connect P+ and P±n on center
airbag sensor assembly side of connector between
center airbag sensor assembly and front passen-
ger airbag.
4. Connect negative (±) terminal cable to battery, and wait at least 2 seconds.
1. Turn ignition switch AAC or ON, and wait at least 20 seconds.
Clear malfunction code. Turn ignition switch LOCK
and wait at least 20 seconds.
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.
Diagnostic trouble code 15 is not output.
Code other than code 15 may be output at this time, but
this is not relevant to this check.
Replace center airbag sensor assembly.
From the results of the above inspection, the malfunctioning part can now be\
considered normal. To
make sure of this, use the simulation method to check.
RS±100±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTING
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DTC22SRS Warning Light System Malfunction
CIRCUIT DESCRIPTION
The SRS warning light is located on the combination meter.
When the supplemental restraint system is normal, the SRS warning light ligh\
ts up for approx. 6 seconds after
the ignition switch is turned from LOCK position to ACC or ON position, and then turn\
s off automatically. If there
is a malfunction in the supplemental restraint system, the SRS warning l\
ight lights up to inform the driver of the
abnormality.
When terminals Tc and E
1 of the DLC2 are connected, the diagnostic trouble code is displayed by the blinking
of the SRS warning light.
The SRS warning light circuit is equipped with an electrical connection che\
ck mechanism which detects when
the connector to the center airbag sensor assembly is not properly connecte\
d.
If the connector to the center airbag sensor assembly is not properly conn\
ected, the SRS warning light will not
light up.
Diagnostic trouble code 22 is recorded when a malfunction occurs in the SRS warnin\
g light system. If an OPEN
malfunction occurs in the SRS warning light system, the SRS warning light does not light up, so that until the
malfunction is repaired, the diagnostic trouble codes (including 22) c\
annot be confirmed.
DTC No.Trouble Area
22 Open circuit in SRS warning light system.
 Center airbag sensor assembly malfunction.
RS±102±
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