GM Service Manual Online
For 1990-2009 cars only

Object Number: 491232  Size: MF
Theft Deterrent System Components
Theft Deterrent Passlock ™ Lock Cylinder

Circuit Description

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

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

In the case of a tamper condition, the BCM will be reading a tamper code.

Conditions for Running the DTC

The ignition switch is cycled to CRANK and released to ON.

Conditions for Setting the DTC

    • The BCM will inspect for a tamper code when the ignition switch rotates from ON to CRANK and will continue to monitor the signal during the engine running period.
    • The BCM is reading a tamper code from the Passlock sensor for longer than 1second.

Action Taken When the DTC Sets

    • The BCM enters tamper mode.
    • If the DTC sets while the engine is running, the car will start on future attempts and the theft indicator flashes.
    • The SERVICE VEHICLE SOON indicator illuminates.

Conditions for Clearing the DTC

    • The BCM is programmed and learns the correct ignition cylinder key code.
    • Current DTCs will clear after one ignition cycle if the malfunction is no longer present.
    • All of the BCM history codes will be cleared after 100 ignition cycles (from OFF to ON) with no current codes active during the 100 ignition cycles.

Diagnostic Aids

    • Inspect for a damaged Passlock™ sensor in the ignition switch.
    • If the DTC is a history DTC the problem may be intermittent. Perform the tests shown while wiggling the wiring and connectors. This will cause the malfunction to appear.

Test Description

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

  1. Tests the magnet placement and inspects the ignition lock cylinder for a mechanical problem.

Step

Action

Yes

No

1

Was the Theft Deterrent Diagnostic System Check performed?

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 B3033 as a current DTC?

Go to Step 3

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

3

Visually inspect the ignition lock cylinder and the magnet attached to it.

Is there any physical damage or is the magnet loose?

Go to Step 4

Go to Step 7

4

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 10

--

5

Inspect for poor connections at the BCM. 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 6

6

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

Important: Perform the setup procedure for the body control module. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

Did you complete the replacement?

Go to Step 10

--

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.

Important: Perform the relearn procedure for the Passlock™ sensor. Refer to Programming Replacement Lock Cylinder, Body Control Module or Powertrain Control Module .

Did you complete the replacement?

Go to Step 9

--

9

Perform the Passlock™ learn procedure. Refer to Programming Replacement Lock Cylinder, Body Control Module or Powertrain Control Module .

Is the repair complete?

Go to Step 10

--

10

  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 5

System OK