Air Bag Indicator Circuit Malfunction

Air Bag Indicator Circuit Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.

Circuit/System Description

When the ignition is turned ON, the instrument panel cluster (IPC) flashes the SIR Air Bag warning indicator 7 times for a bulb check. The inflatable restraint sensing and diagnostic module (SDM) performs diagnostic tests on the SIR system during the bulb check. If any malfunction exists the SDM will request the IPC to illuminate the air bag warning indicator steady, via serial data. If a preexisting malfunction exists, the air bag warning indicator will illuminate steady immediately after the ignition is turned ON. If the ignition 1 voltage is outside of the normal operating voltage range 9-16 volts, the SDM will command the IPC to illuminate the air bag warning indicator with no DTCs present, then disables all deployment loops.

Diagnostic Aids

* If the ignition 1 voltage for the SDM is outside of the normal operating voltage range, 9-16 volts, the air bag warning indicator will continuously illuminate and no DTC will set.
* The loss of serial data communication between the SDM and the IPC will cause the air bag warning indicator to continuously illuminate.

Reference Information
Schematic Reference

SIR Schematics ([1][2]Air Bag Systems)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

SIR System Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Testing

1. Ignition ON, with a scan tool, verify the Battery Voltage Signal Parameter is 9-16 volts.

• If not the specified range, refer to Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview).

2. Ignition OFF, observe the SIR Air Bag warning indicator while turning the ignition ON. The SIR warning indicator should flash 7 times and then turn OFF.

• If the SIR warning indicator continually flashes, program the SDM.
• If the SIR warning indicator remains on steady, test for Current DTCs. Refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code Descriptions).

3. Ignition ON, with a scan tool command the I/P indicators ON and OFF. The Air Bag indicator should turn ON and OFF when changing between the commanded states.

• If the air bag indicator does not illuminate as expected, replace the IPC.

4. If all tests are normal, replace the SDM.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* SIR/SRS Wiring Repairs (Component Tests and General Diagnostics)
* Control Module References (Programming and Relearning) for SDM and IPC replacement, setup, and programming