GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2001 🢒 Regal (China) 🢒 Body and Accessories 🢒 Theft Deterrent 🢒 DTC B2960

Circuit Description

The body control module (BCM) supplies a 5 volt signal and a ground circuit for the PASS-Key® system. When the Ignition key is inserted into the ignition cylinder and turned to the ON position the BCM reads the PASS-Key® resistance value. The BCM compares the resistance value of the key resistance to the valid resistance programmed into the BCM. If the correct value is read, the BCM sends a class 2 message containing the enable password to the powertrain control module (PCM).

Conditions for Setting the DTC
    • The resistance level sampled at the BCMs PASS-Key® signal circuit is one of 15 valid but incorrect resistance ranges, signaling an invalid PASS-Key® detection.
    • This condition must be present for 1 second.

Action Taken When the DTC Sets
    • The BCM stores DTC B2960 in memory.
    • The BCM sends a class 2 message to the instrument cluster to flash the SECURITY indicator.
    •  The BCM sends a class 2 message containing the disable password to the PCM.
    • The vehicle will not start.
    • The BCM disables sampling of the PASS-Key® resistance value for a time-out period of 3 minutes.

Conditions for Clearing the DTC
    • This DTC requires an ignition cycle in order to change from current to history.
    • The BCM detects a valid PASS-Key® resistance value on the PASS-Key® signal circuit after the 3 minute time-out period occurs.
    • A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
    • Use a scan tool.

Diagnostic Aids
    • The following conditions may cause an intermittent malfunction:
       - There is an intermittent open or short to ground on the PASS-Key® signal or ground circuit.
       - There are poor connections at the BCM or the ignition switch connector.
       - The ignition lock cylinder key contacts or the PASS-Key® resistor are dirty or loose.
    • If the incorrect value is read, the BCM sends a class 2 message containing the disable password to the powertrain control module (PCM). This state will last about 3 minutes. If a key is inserted, or the ignition is turned ON again before the 3 minute time frame is complete, the timer will reset to 3 minutes. Disconnecting the battery will not clear the timer sequence, but the timer will reset to 3 minutes when the battery power is restored. Even if a proper key is inserted during one of the time periods, the vehicle will not start until the total time period has elapsed.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. Tests for other PASS-Key® DTCs stored in the BCM that will cause a DTC B2960 to set. These DTCs must be diagnosed first.

    2.

  2. Tests for an intermittent or incorrect PASS-Key® Resister reading due to an incorrect or malfunctioning ignition key.

Step

Action

Yes

No

Schematic Reference: Theft Deterrent System Schematics

1

Did you perform the Theft Deterrent Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Theft Deterrent

2
  1. Install a scan tool.
  2. Turn ON the ignition with the engine OFF.
  3. Select the Display DTCs function for the BCM.

Does the scan tool display DTC B2960 as a current DTC?

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections

3

Does the scan tool display DTC B2957 or B2958 as a current DTC?

Go to Diagnostic Trouble Code (DTC) List

Go to Step 4

4

Inspect the ignition key for dirt or obvious damage.

Does the ignition key appear dirty or damaged?

Go to Step 10

Go to Step 5

5
  1. Turn off the ignition.
  2. Disconnect the ignition lock cylinder connector.
  3. Connect a J 35628-A Vats/Passkey Interrogator J35628-A to the ignition key resistor signal circuit and the low referance circuit.
  4. Note: This step may take as long as 45 minutes due to a trial and error process. Turn the rotary switch on the J 35628-A to each code number (1-15) and attempt to start the vehicle with each code number. (After each failed starting attempt, you must wait 3 minutes before the next attempt.)
  5. Attempt to start the vehicle.

Does the vehicle start with one of the codes selected on the J 35628-A?

Go to Step 6

Go to Step 7

6
  1. Note the code number on the J 35628-A that successfully started the vehicle.
  2. Obtain and cut a new ignition key with the correct key code value.
  3. Attempt to start the vehicle with the new ignition key.

Does the vehicle start?

Go to Step 13

Go to Step 8

7

Test the following circuits for an open or a short:

    • The key resistor input circuit
    • The key resistor reference ground circuit

Did you find and correct the condition?

Go to Step 13

Go to Step 9

8

Inspect for poor connections at the harness connector of the ignition lock cylinder. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 11

9

Inspect for poor connections at the harness connector of the body control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 12

10

Clean or replace the ignition key as necessary. Refer to Replacing Keys .

Did you complete the action?

Go to Step 13

--

11

Replace the ignition lock cylinder. Refer to Ignition Lock Cylinder Replacement - On Vehicle in Steering Wheel and Column.

Did you complete the replacement?

Go to Step 13

--

12

Important: When replacing the BCM, perform the relearn procedure. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

Replace the BCM. Refer to Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 13

--

13
  1. Use the scan tool in order to clear the DTCs.
  2. Attempt to start the vehicle.

Does the DTC reset?

Go to Step 2

System OK