Component Tests and General Diagnostics

Sensing and Diagnostic Module Integrity Check

The following diagnostic procedure must be used when all circuitry outside the sensing and diagnostic module (SDM) has been found to operate properly, as indicated by following the appropriate DTC table. The procedure verifies the need for SDM replacement.

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using the diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

Circuit/System Description

When the SDM recognizes ignition voltage greater than 9 volts at the SDM, the air bag indicator flashes 6 times to verify operation. At this time the SDM performs turn-on tests followed by resistance measurement tests and continuous monitoring tests.

When malfunction is detected, the SDM sets a current DTC and illuminates the air bag indicator.

When the malfunction is no longer detected and/or the ignition switch is cycled, the SDM will clear current DTCs and move them to a history file, except for the DTCs B1620, B1650, B1651, B1652, B1657. These DTCs will not be cleared by a scan tool because these codes require replacement of the SDM. The SDM must be replaced only after the malfunction that set the DTC has been repaired.

Reference Information
Schematic Reference

SIR Schematics (without WHB) (SIR Schematics (without WHB))SIR Schematics (with WHB) (SIR Schematics (with WHB))
Connector End View Reference

Component Connector End Views (Connector Views)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Circuit/System Testing

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 I/P module
* The SDM module
* The I/P wiring harness connector
* The SDM wiring harness connector

1. Turn the ignition to LOCK and remove the key.
2. Connect all supplemental inflatable restraint (SIR) components and ensure that all the components are properly mounted.
3. Ensure that the ignition switch has been OFF for at least 30 seconds.
4. Ignition ON, observe the air bag indicator flashes 6 times.

• If air bag indicator does not flash 6 times, and same DTC is set again, replace the SDM.

• If air bag indicator does not flash 6 times, and different DTC is set then previous, refer to Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle).

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

Control Module References (Programming and Relearning) for SDM replacement, setup, and programming