2010 Cadillac CTS Sedan AWD V6-3.6L Page 267
* IPC
* XBCM
* DDM
* PDM
瀚慖f any modules 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.
2. If all modules VIN match, replace the RCDLR.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
Control Module References (See: Testing and Inspection/Programming and Relearning) for XBCM, RCDLR, IPC, DDM, PDM replacement,
setup, and programming
Without Y41
DTC B0996 (without Y41)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
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 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 immobilizer system considers this to be a tamper 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.
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 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.
