For 1990-2009 cars

### Circuit Description

When the ignition switch is turned to ON, the sensing and diagnostic module (SDM) will perform a turn-on test to diagnose critical malfunctions within the SDM itself.

In case of the 1st stage air bag inflation by a vehicle collision, the SDM maintains the warning lamp ON and all the air bag systems including the SDM, air bag module, and wiring should be replaced.

### DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B1650 Frontal Stage 1 Deployment Commanded

### Conditions for Running the DTC

Ignition voltage is within the normal operating voltage range.

### Conditions for Setting the DTC

The history of the 1st stage air bag inflation or the belt pretensioner explosion is in the SDM.

### Action Taken When the DTC Sets

The SDM commands the AIR BAG indicator ON.

### Conditions for Clearing the DTC

The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.

Warning: Refer to Sensing and Diagnostic Module Voltage after Ignition is Turned Off Warning in the Preface section.

Warning: Refer to Sensing and Diagnostic Module Handling Warning in the Preface section.