DTC B0996
Diagnostic Instructions
DTC Descriptor
DTC B0996 00 : Vehicle Electronic Control Unit (ECU) VIN Check Error
Circuit/System Description
After battery power has been restored following a loss of power, the theft deterrent module (TDM) will perform a check on the stored vehicle identification number (VIN). If the VIN is CORRECT, the TDM will run the VIN Timer for a programmable length of time, typically 10 minutes. The TDM will send a message via the serial data circuit to the instrument panel cluster (IPC) to illuminate the SECURITY indicator. After the VIN Timer has timed out, the security indicator will turn OFF. If the VIN is INCORRECT, the TDM will send the fuel disable password to the engine control module (ECM), via the serial data circuit. The immobiliser system considers this to be an indication of tampering and will not allow the vehicle to start. The TDM will send a message via the serial data circuit to the IPC to flash the SECURITY indicator.
Conditions for Running the DTC
Ignition ON
Conditions for Setting the DTC
• | The VIN check flag of the TDM is true. |
• | The TDM has determined that the battery has been reconnected after a battery disconnect. |
Action Taken When the DTC Sets
• | The vehicle will not start. |
• | The TDM sends the fuel disable message via the serial data circuit to the ECM. |
• | The TDM will run the VIN Timer for a programmable length of time, typically 10 minutes. |
• | The TDM sends a message to the IPC to illuminate the SECURITY indicator. |
Conditions for Clearing the DTC
The TDM clears the current DTC when the correct VIN information is present.
Reference Information
Schematic Reference
Immobiliser Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Immobiliser Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- With a scan tool, verify that the VIN in any module which stores the vehicle VIN matches the actual vehicle VIN:
⇒ | If any module's stored VIN does not match the actual VIN, perform the setup procedure for that module. If the stored VIN does not match after setup, replace the module. |
- If the stored VINs of all modules match the actual VIN, replace the TDM.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for control module replacement, setup, and programming
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