B2500

DTC B2500

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.

DTC Descriptor
DTC B2500
- SIR System Indicator Circuit

Circuit/System Description

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

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

If the warning lamp operates properly ON and OFF, the SDM measures the voltage continuously from the warning lamp terminal.

Conditions for Running the DTC

Ignition voltage is within the normal operating voltage range.

Conditions for Setting the DTC

The warning lamp does not blink properly ON and OFF.

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.

Reference Information
Schematic Reference

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

Component Connector End Views (Connector End Views By Name)
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.

* IPC
* SDM
* IPC wiring harness connector
* SDM wiring harness connector

1. Disconnect the instrument panel cluster (IPC) connector.
2. Ignition ON, check for 9-16V at terminal 5 X1 of the IPC wiring connector.

• If voltage is not as specified, test circuit for an open, high resistance or short to ground.

3. Inspect the connection between terminal 5 X1 and 27 X2 of the IPC.

• If connection is not OK, replace the IPC.

4. Ignition OFF, disconnect the X2 connector of the inflatable restraint sensing and diagnostic module (SDM).
5. Check for 0 ohms between terminal 5 X1 of IPC connector and terminal 5 X2 of the SDM connector.

• If resistance is not as specified, test circuit for an open or high resistance.

6. Check for infinite ohms between terminal 5 X2 of the SDM connector and ground, battery positive.

• If resistance is not as specified, test circuit for a short to ground or short to voltage.

• If resistance is as specified, replace the SDM.

Repair Instructions

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

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