GM Service Manual Online
For 1990-2009 cars only

Object Number: 573265  Size: LF
Theft Deterrent System Components
Theft Deterrent System Schematics
Theft Deterrent System Schematic Icons

Circuit Description

The body control module (BCM) will read an analog voltage form the Passlock™ sensor. Based on an internal reference, the BCM will determine if the measured voltage is in one of the following conditions:

    • Open
    • Shorted to ground
    • A valid code
    • A tamper code

There are 10 possible valid code combination. The BCM will only recognize the last learned valid code.

Conditions for Setting the DTC

    • The BCM will inspect for a valid code when the ignition is rotated from ON to CRANK and will continue to monitor the signal during the engine running period.
    • The BCM is reading a valid but different code value than previously learned form the Passlock™ sensor.

Action Taken When the DTC Sets

    • The vehicle will not start if the fault occurs before you start the vehicle. The security telltale will be FLASHING.
    • If the vehicle is running when the fault occurs, the BCM will be in the fail enable mode allowing the vehicle to start and run. The security telltale will be ON.

Conditions for Clearing the DTC

    • The DTC will clear once an ignition cycle occurs without the fault recurring.
    • The BCM history codes will clear once 100 concurrent ignition cycles occur without the fault recurring.
    • Using a scan tool.

Diagnostic Aids

    • When replacing the Passlock™ sensor, all of the following components are included as a replacement part and must be replaced:
       - The lock
       - The sensor
       - The filter
       - The harness
    • Use a scan tool in order to inspect the Passlock™ data voltage and the Passlock™ code.
    • Inspect the Passlock™ sensor harness for an intermittent or a short to battery. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

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

  1. Tests for the proper operation of the circuit in the normal voltage range.

Step

Action

Value(s)

Yes

No

1

Did you perform the Theft Deterrent (VTD) Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Theft Deterrent

2

  1. Install a scan tool.
  2. Momentarily rotate the ignition switch to CRANK (do not start the vehicle).
  3. Release the ignition switch to ON.
  4. Select the body control module display DTCs function on the scan tool.

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 B2947, B2948, B2957, or B2958?

--

Go to Diagnostic Trouble Code (DTC) List/Type

Go to Step 4

4

Have you replaced the Passlock™ sensor on this vehicle?

--

Go to Step 5

Go to Step 6

5

Have you performed a Passlock™ learn procedure after replacing the Passlock™ sensor?

--

Go to Step 6

Go to Step 9

6

With a scan tool, observe the Passlock™ data voltage for one minute.

Does the scan tool indicate that the Passlock™ data voltage is changing more than the specified value?

+/- 0.02v

Go to Step 7

Go to Step 9

7

Inspect for poor connections at the Passlock ™ sensor. 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 10

Go to Step 8

8

Replace the Passlock™ sensor in the electronic column lock module assembly. Use the appropriate procedure from the following list:

    • Tilt Wheel
       - With column shift
             1. Disassemble Electronic Column Lock Module - Disassemble - Off Vehicle
             2. Assemble Electronic Column Lock Module - Assemble - Off Vehicle
       - With floor shift
             1. Disassemble Electronic Column Lock Module - Disassemble - Off Vehicle
             2. Assemble Electronic Column Lock Module - Assemble - Off Vehicle
       - Export
             1. Disassemble Electronic Column Lock Module - Disassemble - Off Vehicle
             2. Assemble Electronic Column Lock Module - Assemble - Off Vehicle
    • Standard Wheel
       - With column shift export
             1. Disassemble Electronic Column Lock Module - Disassemble - Off Vehicle
             2. Assemble Electronic Column Lock Module - Assemble - Off Vehicle
       - With floor shift export
             1. Disassemble Electronic Column Lock Module - Disassemble - Off Vehicle
             2. Assemble Electronic Column Lock Module - Assemble - Off Vehicle

Did you complete the replacement?

--

Go to Step 9

--

9

Perform one of the following Passlock™ learn procedures:

    •  PASSLOCK Reprogramming Seed and Key (10 minutes).
    •  PASSLOCK Reprogramming Auto Learn (30 minutes).

Is the repair complete?

--

Go to Step 10

--

10

  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition
  3. Momentarily rotate the ignition switch to CRANK (do not start the vehicle).
  4. Release the ignition switch to ON.
  5. Select the body control module display DTCs function on the scan tool.

Does the DTC reset?

--

Go to Step 3

System OK