For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### Circuit/System Description

When the ignition is turned ON, the instrument panel cluster (IPC) flashes the AIR BAG indicator 7 times. The inflatable restraint sensing and diagnostic module (SDM) performs diagnostic tests on the SIR system and then commands the IPC to turn the AIR BAG indicator OFF if no SIR malfunction exists. The AIR BAG indicator is controlled by the SDM via serial data communications. 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 indicator with no DTCs present then disables all deployment loops.

### Reference Information

#### Schematic Reference

SIR Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

SIR System Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Diagnostic Aids

A DTC B1325 may set if the ignition 1 circuit is outside the 9-16 volts range.

### Circuit/System Testing

1. Ignition ON, observe the function of the air bag indicator lamp, the indicator lamp will flash 7 times and go OFF.

⇒ | If the air bag indicator continuously illuminates, check the serial data signal circuit for a short to ground or an open/high resistance.

⇒ | If the air bag indicator continually flashes, program the SDM.

2. Command the AIR BAG indicator ON and OFF with a scan tool, refer to Body/Actuator Test/Telltale Test. The indicator should turn ON and OFF while changing between the commanded states.

⇒ | If the AIR BAG indicator does not illuminate, replace the IPC.

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

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | SIR/SRS Wiring Repairs

• | Control Module References for IPC and SDM replacement, setup, and programming