Lexus SC300 / Lexus SC400. Manual — part 46

Check spiral cable.

Repair or replace spiral cable.

Measure resistance between D+ and D– on center
airbag sensor assembly side of connector between
center airbag sensor assembly and spiral cable.

Check harness between center airbag sensor assembly and spiral
cable.

Resistance: Below 1

Measure resistance between D+ and D– on spiral
cable side of connector betweenspiral cable and
steering wheel pad.

Resistance: Below 1

Disconnect connector between center airbag sensor
assembly and spiral cable.

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

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SRS AIRBAG

Troubleshooting

AB–65

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

Replace center airbag sensor assembly.

AB–66

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SRS AIRBAG

Troubleshooting

MEMO

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SRS AIRBAG

Troubleshooting

AB–67

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Diag. Code 15

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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

AB–5

.

Diagnostic 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

AB–7

). This mechanism is

constructed so that when the terminals of the front airbag sensor have been connected (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 system 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 connected, check again that it is properly
connected.

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Code No.

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Diagnosis

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15

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

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.

AB–68

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SRS AIRBAG

Troubleshooting