Supplemental Inflatable Restraints

DTC B0996

Diagnostic Instructions

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



DTC Descriptor
DTC B0996 00
- Vehicle Electronic Control Unit (ECU) VIN Check Error




Circuit/System Description

The inflatable restraint sensing diagnostic module (SDM) and the body control module (BCM) are programmed with the vehicle identification number (VIN). When the ignition is in the RUN position the BCM requests the SDM to transmit the VIN via serial data and compares the VIN number stored in the SDM to that stored in the BCM. If the BCM identifies a mismatch this DTC will set.


Conditions for Running the DTC

System voltage is between 9-16 volts.


Conditions for Setting the DTC

* The VIN message received via the GMLAN does not match the VIN number stored in the SDM.
* The incorrect SDM is installed on the vehicle.
* The incorrect software or calibrations have been flash programmed into the SDM.



Action Taken When the DTC Sets

DTC B0996 00 will set in the event of a VIN mismatch. There will be no indication to the driver unless the SDM is one of three modules that have a VIN mismatch fault. In the event of three modules failing to have the correct VIN stored the vehicle will fail to start.


Conditions for Clearing the DTC

* The condition for setting the DTC is no longer present.
* A history DTC will clear once 250 malfunction-free ignition cycles have occurred.



Reference Information
Schematic Reference

SIR Schematics ([1][2]Air Bag Systems)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

SIR System Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information


Circuit/System Verification

1. Ignition ON, verify that DTC B0996 is not set.

• If the DTC is set, program the SDM.

2. If the DTC resets, replace the SDM.



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