code 32 LEXUS SC300 1991 Service Service Manual

Page 182 of 4087


Check center airbag sensor assembly.
Diagnostic code 14 is not output.(1) Connect connector to center airbag sensor
connector.
(2) Connect connector between center airbag sensor assembly and spiral cable.
(3) Using a service wire, connect D+ and D± on spiral cable side of connector between spiral
cable and steering wheel pad.
(4) Connect negative (±) terminal cable to battery,
and wait at least 2 seconds.
Check squib.
(1) Turn ignition switch ACC or ON, and wait at least 20 seconds.
(2) Using SST, connect terminals Tc and E1 of TDCL.
SST 09843±18020
(3) Check diagnostic code.
(1) Turn ignition switch LOCK.
(2) Disconnect battery negative (±) terminal cable, and wait at least 20 seconds.
(3) Connect steering wheel pad (squib) connector.
(4) Connect negative (±) terminal cable to battery, and wait at least 2 seconds.
Diagnostic code 14 is not output. (1) Turn ignition switch ACC or ON, and wait at least 20 seconds.
(2) UsingSST, connect terminals Tc and E1 of TDCL.
SST 09843±18020
(3) Check diagnostic code. Codes other than code 14 may be output at this
time, but this is not relevant to this check
Codes other than 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 no\
w be considered normal.
To make sure this, use the simulation method to check. Replace center airbag sensor assembly.
AB±66±
SRS AIRBAG Troubleshooting
WhereEverybodyKnowsYourName

Page 184 of 4087


 
Diag. Code 15\
 \
Open in Front Airbag Sensor Circuit
CIRCUIT DESCRIPTION
The front airbag sensor detects the deceleration force in a frontal collisi\
on and is located in the front fender
on the left and right sides.
For details of the function of each component, see FUNCTION OF COMPONENT\
S on page AB±5.
Diagnostic code 15 is recorded when an open is detected in the front air\
bag sensor circuit.
NOTICE: The front airbag sensor connector is equipped with an electrical connection \
check mechanism
for the purpose of detecting an open in the front airbag sensor (See page AB±7). This mechanism is
constructed so that when the terminals of the front airbag sensor have been connect\
ed (when the connec-
tor housing lock is in the locked condition), the connection detection \
pin on the wire harness side connects
with the terminals for diagnosis use on the sensor side. If the connector is\
not properly connected, the diag-
nosis system may detect only a malfunction code, even though the airbag syste\
m is functioning normally.
When connecting the front airbag sensor connector, make sure it is connected properly. If diagnostic code
15 is displayed after the front airbag sensor connector has been connect\
ed, check again that it is properly
connected.
 

Code No.
\
 
\

\
Diagnosis
 




15
\
 
\


\

\


Open circuit in +S wire harness or ±S wire harness of front airbag s\
ensor.
 Front airbag sensor malfunction.
 Malfunction of electrical connection check mechanism of front airbag se\
nsor.
 Center airbag sensor assembly malfunction.
AB±68±
SRS AIRBAG Troubleshooting
WhereEverybodyKnowsYourName

Page 187 of 4087


3
Codes other than code 15 may be output at this
time, but this is not relevant to this check.Replace front airbag sensor.
NG
OK
(1) Turn ignition switch ACC or ON, and wait at least 20
seconds.
(2) Using SST, connect terminals Tc and E
1 of TDCL.
SST 09843±18020
(3) Check diagnostic code.
Check center airbag sensor assmbly.
Check front airbag sensor.
Replace center airbag sensor assembly.NG
OK
Diagnostic code 15 is not output.
(1) Connect connector to center airbag sensor
assembly.
(2) Using a service wire, connect D+ and D± on spiral cable side of connector between spiral
cable and steering wheel pad.
(3) Connect negative (±) terminal cable to battery, and wait at least 2 seconds.
From the results of the above inspection, the malfunctioning part can no\
w be considered normal.
To make sure of this, use the simulation method to check.
4
Disconnect front airbag sensor connector. Measure resistance between each terminal of
front airbag sensor.
 Do not touch ohmmeter probes strongly
against terminals of front airbag sensor.
 Make sure the front airbag sensor connector
is properly connected.
Terminal Resistance
Below 1 
755
 ±885 
1 M or higher
+S ± +A
+S ± ±S
±S ± ±A
±
SRS AIRBAG TroubleshootingAB±71
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Page 190 of 4087


Diag. Code 22Airbag Warning Light System Malfunction
CIRCUIT DESCRIPTION
The airbag warning light is located on the combination meter.
When the airbag system is normal, the airbag warning light lights up for\
approx. 6 seconds after the
ignition switch is turned from LOCK position to ACC or ON position, and then turns off automatically.
If there is a malfunction in the airbag system, the airbag warning light\
lights up to inform the driver of
the abnormality.
When terminals Tc and E of the TDCL are connected, the diagnostic code is displayed by t\
he blinking
of the airbag warning light.
The airbag warning light circuit is equipped with an electrical connecti\
on check mechanism which
detects when the connector to the center airbag sensor assembly is not p\
roperly connected.
If the connector to the center airbag sensor assembly is not properly co\
nnected, the airbag warning
light will not light up.
Diagnostic code 22 is recorded when a malfunction occurs in the airbag w\
arning light system.
If an OPEN malfunction occurs in the airbag warning light system, the ai\
rbag warning light does not
light up, so that until the malfunction is repaired, the diagnostic code\
s (including code 22) cannot be
confirmed.
Code No.Diagnosis
22 Open circuit in airbag warning light system.22 Center airbag sensor assembly malfunction.
AB±74±
SRS AIRBAG Troubleshooting
WhereEverybodyKnowsYourName

Page 191 of 4087


OKNG
1
2
3
4
5
6
6
OK
OK
YES
YES NG
NG NO
NO
Check connection of center airbag sensor
assembly connector.
Preparation.
Check airbag warning light circuit.
Does airbag warning light come on?
Is new ECU ±B fuse burnt out again? GO to step
Repair.
Repair airbag warning light circuit
(See page BE±150).
Check terminal LA of center
airbag sensor assembly and
electrical connection check
mechanism. If normal, replace
center airbag sensor assembly.
Using simulation method,
reproduce malfunction symptoms
(See page IN±20).
Check harness between ECU ±B fuse and
airbag warning light, and ECU±B fuse and
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.
Check ECU ±B fuse.
DIAGNOSTIC CHART
Troubleshooting for this system is different for when the airbag warning light does not light up and for
when diagnostic code 22 is output. Confirm the problem symptoms first before\
selecting the appropriate
troubleshooting procedure.
HINT: If airbag warning light does not light up, perform the following troub\
leshooting:
±
SRS AIRBAG TroubleshootingAB±75
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Page 192 of 4087


YESNO
1
Replace center airbag sensor assembly. Using simulation method,
reproduce malfunction symptoms
(See page
IN±20).
WIRING DIAGRAM
Is diagnostic code 22 output again?
DIAGNOSTIC CHART
HINT: If diagnostic code 22 is output, perform the following troubleshooting:\
AB±76
±
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WhereEverybodyKnowsYourName

Page 195 of 4087


1
Using simulation method, reproduce malfunction
symptoms (See page IN±20).NO
YES
(1) Turn ignition switch LOCK, and wait at least 2
seconds.
(2) Turn ignition switch ACC or ON, and wait at least 20 seconds.
(3) Using SST, connect terminals Tc and E
1 of TDCL.
SST 09843±18020
(4) Check diagnostic code. Clear malfunction code 41 stored in memory
(See page
AB±35).
Is diagnostic code 22 output again?
Replace center airbag sensor assembly.
HINT: If diagnostic code 22 is output, perform the following troubleshooting\
:
±
SRS AIRBAG TroubleshootingAB±79
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Page 196 of 4087


YES
Is diagnostic code 31 output again?
NO
1
Replace center airbag sensor assembly. Using simulation method, reproduce
malfunction symptoms
(See page
IN±20).
Diag. Code 31Center Airbag Sensor Assembly Malfunction
CIRCUIT DESCRIPTION
The center airbag sensor assembly consists of a 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 a\
irbag must be activated, and
diagnoses system malfunction.
Diagnostic code 31 is recorded when occurrence of a malfunction in the center airba\
g sensor assembly
is detected.
Code No.Diagnosis
31 Center airbag sensor assembly malfunction.
DIAGNOSTIC CHART
HINT: When a malfunction code other than code 31 is displayed at the same tim\
e, first repair the
malfunction indicated by the malfunction code other than code 31.
AB±80
±
SRS AIRBAG Troubleshooting
WhereEverybodyKnowsYourName

Page 197 of 4087


1
NG
OK
(1) Turn ignition switch LOCK, and wait at least 20
seconds.
(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 TDCL.
SST 09843±18020
(5) Check diagnostic code.
Is diagnostic code 31 output again?
Using simulation method, reproduce
malfunction symptoms (See page IN±20).
Clear malfunction code stored in memory
(See page
AB±32).
Replace center airbag sensor assembly.
INSPECTION PROCEDURE
HINT:When a malfunction code other than code 31 is displayed at the same time, fi\
rst repair the malfunction indicated by the malfunction code other than code 31.
±
SRS AIRBAG TroubleshootingAB±81
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Page 198 of 4087


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
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