Lexus SC300 / Lexus SC400. Manual — part 800

OK

NG

OK

NG

3

Check spiral cable.

C

OK

P

Disconnect connector between center airbag sensor
assembly and spiral cable.

Measure resistance between D

+

and D– on spiral cable

side of connector between spiral cable and steering
wheel pad.

Resistance:

Below 1

Repair or replace spiral cable.

4

Check harness between center airbag sensor assembly and spiral cable.

C

OK

Measure resistance between D

+

and D– on center air-

bag sensor assembly side of connector between center
airbag sensor assembly and spiral cable.

Resistance:

Below 1

Repair or replace harness or connector between center
airbag sensor assembly and spiral cable.

–

SUPPLEMENTAL RESTRAINT SYSTEM

TROUBLESHOOTING

RS–95

OK

NG

OK

NG

5

Check center airbag sensor assembly.

C

OK

Hint

P

1.

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.

6

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, 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 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 now be considered normal. To
make sure of this, use the simulation method to check.

RS–96

–

SUPPLEMENTAL RESTRAINT SYSTEM

TROUBLESHOOTING

DTC

15

Open in Front Airbag Sensor Circuit

CIRCUIT DESCRIPTION

The front airbag sensor detects the deceleration force in a frontal collision and is located in the front fender on
the left and right sides.
For details of the function of each component, see FUNCTION OF COMPONENTS on page

RS–10

. Diagnostic

trouble code 15 is recorded when an open is detected in the front airbag 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

RS–13

). This mechanism is

constructed so that when the terminals of the front airbag sensor have been connected (when the con-
nector 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 con-
nected, the diagnosis system may detect only a malfunction code, even though the supplemental re-
straint system is functioning normally. When connecting the front airbag sensor connector, make sure
it is connected properly. If diagnostic trouble code 15 is displayed after the front airbag sensor connec-
tor has been connected, check again that it is properly connected.

DTC No.

Diagnosis

15

Open circuit in +S wire harness or –S wire harness of front airbag sensor.

Front airbag sensor malfunction.

Malfunction of electrical connection check mechanism of front airbag sensor.

Center airbag sensor assembly malfunction.

–

SUPPLEMENTAL RESTRAINT SYSTEM

TROUBLESHOOTING

RS–97

WIRING DIAGRAM

DIAGNOSTIC CHART

DIAGNOSTIC CHART

(See page

RS–49

).

(See page

RS–49

).

RS–98

–

SUPPLEMENTAL RESTRAINT SYSTEM

TROUBLESHOOTING