2010 Cadillac CTS Sedan AWD V6-3.6L Page 266

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: