1991 LEXUS SC400 sensor

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

DTC13Short in Squib Circuit (Between D+ Wire Harness
and D
± Wire Harness
CIRCUIT DESCRIPTION
The squib circuit consists of the center airbag sensor assembly, spiral cable and the steering wheel pad (squib).
It causes the SRS to deploy when the SRS deployment conditions are satisfi\
ed.
For details of the function of each component, see FUNCTION OF COMPONENT\
S on page RS±10.
Diagnostic trouble code 13 is recorded when a short is detected in the D+ wire harn\
ess and D wire harness of
the squib circuit.
DTC No.Diagnosis
13
 Short circuit between D+ wire harness and D± wire harness of squib.
 Squib malfunction.
 Spiral cable malfunction.
 Center airbag sensor assembly malfunction.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTINGRS±85
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
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.
5Check spiral cable.
C
OK
P1. Disconnect connector between center airbag sen-sor assembly and spiral cable.
2. Release airbag activation prevention mechanism on center airbag sensor assembly side of spiral
cable connector (See page RS±91).
Measure resistance between D
+ and D± on spiral cable
side of connector between spiral cable and steering
wheel pad.
Resistance: 1 M
or higher
Repair or replace spiral cable.
6Check harness between center airbag sensor assembly and spiral cable.
C
OK
P1. Disconnect center airbag sensor assembly con-
nector.
2. Release airbag activation prevention mechanism on center airbag sensor assembly connector (See
page RS±91 ).
Measure resistance between D
+ and D± on center air-
bag sensor assembly side of connector between center
airbag sensor assembly and spiral cable.
Resistance: 1 M
or higher.
Repair or replace harness or connector between center
airbag sensor assembly and spiral cable.
±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTINGRS±89
WhereEverybodyKnowsYourName

OKNG
7Check center airbag sensor assembly.
C
OK
PConnect center airbag sensor assembly connector.
Measure resistance between D
+ and D± on center air-
bag sensor assembly side of connector between center
airbag sensor assembly and spiral cable.
Resistance: 1 k
or more
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±90±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTING
WhereEverybodyKnowsYourName

DTC14Open in D Squib Circuit
CIRCUIT DESCRIPTION
The squib circuit consists of the center airbag sensor assembly, spiral cable and the steering wheel pad (squib).
It causes the SRS to deploy when the SRS deployment conditions are satisfi\
ed.
For details of the function of each component, see FUNCTION OF COMPONENTS o\
n page RS±9. Diagnostic
trouble code 14 is recorded when an open is detected in the squib circuit.
DTC No.Diagnosis
14
 Open circuit in D+ wire harness or D± wire harness of squib.
 Squib malfunction.
 Spiral cable malfunction.
 Center airbag sensor assembly malfunction.
RS±92±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTING
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NGOK
INSPECTION PROCEDURE
1Preparation.
P1. Disconnect battery negative (±) terminal cable, andwait at least 90 seconds.
2. Remove steering wheel pad. (See page RS±19)
3. Disconnect connectors of front passenger airbag assembly (See page RS±32).
Caution: Store the steering wheel pad with the
surface facing upward.
2Check D squib circuit.
C
OK
PDisconnect center airbag sensor assembly connector.
Measure resistance between D+ and D± on spiral cable
side of connector between spiral cable and steering
wheel pad.
Resistance: Below 1

Go to Step
.
RS±94
±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTING
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