Perform the Diagnostic System Check - SIR prior to using this diagnostic procedure.

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.

Schematic Reference

SIR Schematics

Electrical Information Reference

Caution: The sensing and the diagnosis module (SDM) can maintain sufficient voltage to deploy the airbags and pretensioners for up to 1 minute after the ignition has been turned OFF and the fuse has been removed. If the airbags and pretensioners are not disconnected, do not begin service until one minute has been passed after disconnecting power to the SDM. Failure to do so may cause personal injury.

Caution: Do not strike or jolt the inflatable restraint sensing and diagnostic module (SDM). Before applying power to the SDM, make sure that it is securely fastened with the arrow facing toward the front of the vehicle. Failure to observe the correct installation procedure could cause SIR deployment, personal injury, or unnecessary SIR system repairs.

1. Ignition OFF, disconnect the harness connector at the clock.
2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 4 and ground.

⇒	If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.

3. Connect a test lamp between the control circuit terminal 1 and the ignition circuit terminal 4.
4. With the passenger seat unoccupied, then occupied the test lamp should turn ON and OFF within several seconds.

⇒	If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the SDM.

⇒	If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the SDM.

5. If all circuits test normal, test or replace the Clock.