2010 Cadillac CTS Sedan AWD V6-3.6L Page 266
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC B0996 00
- Vehicle Electronic Control Unit (ECU) VIN Check Error
Circuit/System Description
After a loss of battery power has been restored, the remote control door lock receiver (RCDLR) will perform a check on the stored vehicle
identification number (VIN). If the VIN is CORRECT, the RCDLR will run the VIN Timer for a programmable length of time, typically 10
minutes. The RCDLR 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 RCDLR will send the fuel disable
password to the engine control module (ECM), via the serial data circuit. The immobilizer system considers this to be a tamper and will not allow
the vehicle to start. The RCDLR will send a message via the serial data circuit to the IPC to flash the SECURITY indicator.
Substitution detection is based on correct response from the following modules: instrument panel cluster (IPC), export body control module
(XBCM), driver door module (DDM), passenger door module (PDM). The modules compare their VIN to that stored in the VIN master on every
ignition ON cycle and report their status to the theft deterrent module.
Conditions for Running the DTC
Ignition ON
Conditions for Setting the DTC
* The VIN check flag of the RCDLR is true.
* The RCDLR has determined that the battery has been reconnected after a battery disconnect.
Action Taken When the DTC Sets
* The vehicle will not start.
* The RCDLR sends the fuel disable message via the serial data circuit to the ECM.
* The RCDLR will run the VIN Timer for a programmable length of time, typically 10 minutes.
* The RCDLR sends a message to the IPC to illuminate the SECURITY indicator.
Conditions for Clearing the DTC
The RCDLR clears the current DTC when the correct VIN information is present.
Reference Information
Schematic Reference
Immobilizer Schematics (See: Accessories and Optional Equipment/Antitheft and Alarm Systems/Diagrams/Electrical Diagrams/Immobilizer
Schematics)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Immobilizer Description and Operation (without Y41) (See: Accessories and Optional Equipment/Antitheft and Alarm Systems/Description and
Operation/Immobilizer Description and Operation (Without Y41))Immobilizer Description and Operation (with Y41) (See: Accessories and
Optional Equipment/Antitheft and Alarm Systems/Description and Operation/Immobilizer Description and Operation (With Y41))
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit
Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Wiring Repairs/Wiring Repairs)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Verification
1. With a scan tool, verify the stored VIN in the following modules matches the actual vehicle VIN:
