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

Ignition ON, the IPC commands the SIR indicator flashing for 7 times.

SIR SDM performs SIR diagnostic test. If there is no SIR malfunction, SDM will command the IPC to turn off the SIR indicator. The SDM controls the AIR BAG indicator via serial data communications. If voltage of ignition 1 exceeds 9-16 volts, the SDM will commands the IPC to turn on SIR indicator but no DTC will set, then the deployment loop will be disabled.

### Reference Information

#### Schematic Reference

SIR Schematics

#### Connector End View Reference

SIR Connector End Views

### Diagnostic Aids

If ignition 1 voltage exceeds 9-16 volts, DTC B1370 may set.

### Circuit/System Testing

1. Ignition ON, use the scan tool to request the SIR data list display. Observe the voltage parameter of the battery. Battery voltage reading in the scan tool will be 9-16 volts.

⇒ | If the voltage is less than 9 volts, refer to Diagnostic System Check - Vehicle .

2. Ignition ON, monitor the IPC. SIR warning lamp will flash and then off. Check and verify if the SIR warning lamp flashes and then off.

⇒ | If the SIR warning lamp flashes continuously, reprogram the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Programming and Setup

3. Use the scan tool, go to Body and Accessories, choose Special Functions to Instrument Panel Cluster, select Display Test. Command ON in Display Test may turn on or off all IPC indicators. When IPC indicators are turned on, SIR indicator will on.

⇒ | If not, replace the IPC.

Important: SIR indicator cannot be serviced separately. IPC must be serviced or replaced as an entire set.

4. If the scan tool can turn on and off the SIR indicator, replace the SDM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Refer to Control Module References for IPC replacement, setup and programming