DTC B0996. Cadillac CTS 2005

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 2005 🢒 CTS 🢒 Accessories 🢒 Navigation Systems 🢒 DTC B0996

Circuit Description

After a loss of battery power has been restored, the theft deterrent control module will perform a check on the stored vehicle identification number (VIN). If the VIN is CORRECT, the theft deterrent control module will run the VIN Timer for a programmable length of time, typically 10 minutes. The theft deterrent control module 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 theft deterrent control module will send the fuel disable password to the engine control module (ECM), via the serial data circuit. The vehicle theft deterrent (VTD) system considers this to be a tamper and will not allow the vehicle to start. The theft deterrent control module will send a message via the serial data circuit to the IPC to flash the SECURITY indicator.

Substitution detection is based on 4 correct responses from the following modules: IPC, rear integration module (RIM), driver door module (DDM), front passenger door module (FPDM), left rear door module (LRDM), and the right rear door module (RRDM). 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. The theft deterrent module will only check the modules status to see the 4 correct matches when a battery reconnect has been recognized within the theft deterrent module.

DTC Descriptor

This diagnostic procedure supports the following DTC:

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

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

•	The VIN check flag of the theft deterrent control module is true.

•	The theft deterrent control module has determined that the battery has been reconnected after a disconnect.

Action Taken When the DTC Sets

•	The vehicle will not start.

•	The theft deterrent control module sends the fuel disable message via the serial data circuit to the ECM.

•	The theft deterrent control module will run the VIN Timer for a programmable length of time, typically 10 minutes.

•	The theft deterrent control module sends a message to the IPC to illuminate the SECURITY indicator.

Conditions for Clearing the MIL/DTC

•	The theft deterrent control module clears the current DTC when the correct VIN information is present.

•	The DTC can be cleared by using a scan tool.

Diagnostic Aids

The VIN information is stored during the Setup New VTD Module procedure on a GM SPO replacement part. When the manufacturers enable counter (MEC) is equal to 0, the VIN information cannot be changed. DTC B0996 will set the when the theft deterrent does not receive the required 5 correct VIN responses from the modules which report to the theft deterrent module.

Test Description

The number below refers to the step number on the diagnostic table:

This test checks for proper VIN identification in each module. The theft deterrent module compares the stored VIN of 6 modules to that of the dash integration module (DIM). If any 2 of the 6 modules is mismatched to the VIN stored in the DIM, DTC B0996 will set.

Step

Action

Yes

Schematic Reference: Theft Deterrent System Schematics

Connector End View Reference: Theft Deterrent System Connector End Views

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

With a scan tool, view the stored vehicle identification number (VIN) of the following:

•	The instrument panel cluster (IPC)

•	The rear integration module (RIM)

•	The driver door module (DDM)

•	The front passenger door module (FPDM)

•	The left rear door module (LRDM)

•	The right rear door module (RRDM)

Does the stored VIN of each module equal the actual vehicle VIN?

Go to Step 5

Go to Step 3

Perform the setup procedure for affected module or modules. Refer to Control Module References for replacement, setup, and programming information.

Were you able to successfully perform the procedure?

Go to Step 6

Go to Step 4

Replace the affected module or modules. Refer to Control Module References for replacement, setup, and programming information.

Did you complete the replacement?

Go to Step 6

Important: If a 10 Minute or 30 Minute Re-Learn Procedure is performed, all keys not learned at that time will be erased and will not be recognized. Perform the Adding Keys procedure on all keys or instruct the customer how to perform the Adding Keys procedure. Refer to Adding Keys .

Replace the theft deterrent control module. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 6

Use a scan tool in order to clear the DTCs.
Attempt to start the vehicle.

Does the DTC reset?

Go to Step 2

System OK