GM Service Manual Online
For 1990-2009 cars only

Circuit Description

When an ignition key is inserted into the ignition lock cylinder, the transponder embedded in the head of the key is energized by the exciter coils surrounding the ignition lock cylinder. The energized transponder transmits a signal that contains its unique value, which is received by the theft deterrent control module. The theft deterrent control module then compares this value to a value stored in memory (learned key code). If the value is correct the theft deterrent control module sends the enable password via the serial data circuit to the powertrain control module (PCM).

Conditions for Running the DTC

The ignition switch must be ON. The theft deterrent control module cannot have DTC B1327 set as a current DTC.

Conditions for Setting the DTC

If the transponder value from the ignition key does not match the one stored in memory, the theft deterrent control module sets this DTC. This DTC indicates the use of a key with a transponder value that has not been learned by the theft deterrent control module. The vehicle theft deterrent (VTD) system considers this to be a theft attempt.

Action Taken When the DTC Sets

Important: If the theft deterrent control module is unable to measure the ignition key transponder value for 30 consecutive seconds, after the vehicle has started, the theft deterrent control module will enter a fail enable state. The vehicle will not stall or stop running. If the theft deterrent control module is in a fail enable state when the ignition is turned to OFF, it will remain fail enabled until the next time the vehicle is started. If the theft deterrent control module is fail enabled, the vehicle theft deterrent (VTD) system is NOT active and the vehicle will start. The theft deterrent control module WILL send its enable password even if a transponder value is not received. The theft deterrent control module will remain fail enabled until the module measures a valid key transponder value.

    • Stores DTC B2960
    • The instrument cluster displays SERVICE THEFT SYSTEM message.
    • The vehicle will not start.
    • The theft deterrent control module sends a class 2 message to the instrument cluster to flash the SECURITY indicator.

Conditions for Clearing the MIL/DTC

    • The theft deterrent control module clears the current status of the DTC when it senses a valid, memorized, transponder value from the ignition key.
    • The DTC can be cleared by using a scan tool.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Verifies the condition for setting DTC B2960 is current.

  2. The only method to determine which re-learn procedure to perform.

  3. To set this code, a key with a working transponder that is not learned was read by the theft deterrent control module. For that key to operate the vehicle and one or more learned keys are available, perform the Adding Keys procedure.

  4. To set this code, a key with a working transponder that is not learned was read by the theft deterrent control module. For that key to operate the vehicle and there is only one key available, a 10 Minute or 30 Minute Re-Learn Procedure must be performed.

Step

Action

Yes

No

Schematic Reference: Theft Deterrent System Schematics

Connector End View Reference: Theft Deterrent System Connector End Views

1

Did you perform the Theft Deterrent Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Theft Deterrent

2

Is DTC B2960 set as a current code?

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

3

Are more than one of the vehicle's keys available?

Go to Step 4

Go to Step 6

4

Attempt to start the vehicle using all of the vehicle's available master keys.

Do any of the available master keys start the vehicle?

Go to Step 5

Go to Step 6

5

With a learned master key perform the Adding Keys procedure on the suspect key. Refer to Adding Keys .

Is the procedure complete?

Go to Step 7

--

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 .

Perform the Programming Theft Deterrent System Components procedure. Refer to Programming Theft Deterrent System Components .

Is the procedure complete?

Go to Step 7

--

7

  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK