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 turn the AIR BAG indicator ON with no DTCs present then disables all deployment loops.

### Reference Information

#### Schematic Reference

SIR Schematics

#### Connector End View Reference

SIR 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

• | Scan Tool Data List

• | Scan Tool Data Definitions

### Diagnostic Aids

A DTC B1370 may set if the ignition 1 circuit is outside the 9-16 volts range.

### Circuit/System Testing

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

⇒ | If not the specified range, refer to Diagnostic System Check - Vehicle .

2. Cycle the key from OFF to ON, monitor the IPC. The SIR warning indicator should flash then turn OFF.

⇒ | If the SIR warning indicator continually flashes, reprogram the SDM.

3. With a scan tool, perform the display test to Commanded the IPC indicators ON then OFF. The Air Bag indicator should cycle between the commanded states.

⇒ | If the Air Bag indicator does not cycle between the commanded states, replace the IPC.

4. If 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