GM Service Manual Online
For 1990-2009 cars only

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.