SIR Diagnostic Flow

Circuit Description

The ignition switch supplies ignition positive voltage voltage to the Inflatable Restraint Sensing and Diagnostic Module (SDM) at terminal 10 using the AIR BAG Fuse. When the ignition switch is first turned to the RUN position, the SDM responds by flashing the AIR BAG warning lamp 7 times, then turning the warning lamp OFF, while performing tests on the SIR system.

Diagnostic Aids

Ensure that you diagnose the diagnostic trouble codes in the order specified by the SIR diagnostic system check. Failure to do so may result in the following conditions:

^ Extended diagnostic time

^ Incorrect diagnosis

^ Incorrect parts replacement

Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. This test checks for scan tool communication with SDM module on the Serial Data Line.

2. This test checks for scan tool communications with other modules on the Serial Data Line.

3. This test refers to the appropriate DTC Table and Diagnostic Aids for diagnosis of the current and/or history DTCs.

4. The AIR BAG warning lamp should flash seven times after the ignition switch is first turned to the RUN position.

5. The AIR BAG warning lamp indicates improper operation. This test differentiates a warning lamp stays ON condition or a warning lamp does not come ON condition.