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.

Upon passing these tests, the ignition and deployment loop voltages are measured to ensure that these voltages are within the normal ranges. The SDM monitors the voltages at the driver low and the passenger low to detect shorts to ground or voltage in the deployment loops.

The SDM tests the voltage continuously from the warning lamp terminal.

Ignition voltage is between 9-16 volts.

The passenger ON indicator lamp does not operate depending on the status of passenger presence.

The SDM commands the AIR BAG indicator ON.

Schematic Reference

SIR Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

Note: When removing connectors inspect for damage or corrosion. Damage or corrosion in the following requires repair or replacement of the affected component/connector.

•	The steering wheel coil module

•	The SDM module

•	The steering wheel coil module wiring harness connector

•	The SDM wiring harness connector

1. Ignition OFF, disconnect the clock assembly connector
2. Test for B+ at terminal 1 of the clock wiring connector

⇒	If voltage is not as specified, repair the open, high resistance or short to ground in the circuit.

3. Inspect the bulb of the passenger air bag ON indicator.

⇒	If bulb is bad, replace the bulb.

⇒	If all circuits test normal, replace the clock assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.