Lexus SC300 / Lexus SC400. Manual - part 798

OK

NG

INSPECTION PROCEDURE

1

Preparation.

P

1.

Disconnect battery negative (–) terminal cable, and
wait 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.

2

Check D squib circuit.

C

OK

Measure resistance between D

+

 and D– on spiral cable

side of connector between spiral cable and steering
wheel pad.

Resistance:

1 k

 or higher

Go to step 

.

–

SUPPLEMENTAL RESTRAINT SYSTEM

TROUBLESHOOTING

RS–87

OK

NG

OK

NG

3

Check center airbag sensor assembly.

C

OK

Hint

P

1.

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 than code 13 may be output at this time, but
this is not relevant to this check.

Replace center airbag sensor assembly.

4

Check D squib.

C

OK

Hint

P

1.

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 than 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

OK

NG

OK

NG

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.

5

Check spiral cable.

C

OK

P

1.

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.

6

Check harness between center airbag sensor assembly and spiral cable.

C

OK

P

1.

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

TROUBLESHOOTING

RS–89

OK

NG

7

Check center airbag sensor assembly.

C

OK

P

Connect 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