GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

  1. Turn the ignition OFF.
  2. Roll down the windows.
  3. Close all of the doors.
  4. Connect a scan tool.
  5. Turn the ignition to the ON position.
  6. Using the scan tool, inspect for any DTCs in the body control module (BCM).

Does the scan tool show any DTCs?

--

Go to Diagnostic System Check - Body Control System in Body Controls

Go to Step 2

2

Do the doors lock when using the door lock switch or the transmitter then unlock seconds later?

--

Go to Step 3

Go to Step 8

3

  1. Open the driver door.
  2. Turn ignition OFF.
  3. Remove the key.
  4. Using the scan tool, read the key in ignition switch status.

Does the scan tool show yes?

--

Go to Step 4

Go to Step 7

4

  1. Disconnect connector C201B at steering column.
  2. Using the scan tool, read the key in ignition switch status.

Does the scan tool show yes?

--

Go to Step 5

Go to Step 6

5

  1. Locate and repair CKT 80 (LT GRN) for a short to ground
  2. If no open is found, replace the BCM. Refer to Body Control Module Replacement in Body Control Systems.

Is the repair complete?

--

System OK

--

6

Replace the key in ignition switch. Refer to Ignition Lock Cylinder Replacement - On Vehicle in Steering Wheel and Column Tilt.

Is the repair complete?

--

System OK

--

7

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

Is the repair complete?

--

System OK

--

8

Using the scan tool, command the door lock relay ON.

Do the doors lock?

--

Go to Power Door Locks Switch Inoperative - One

Go to Step 9

9

Replace the door lock relay.

Is the repair complete?

--

System OK

--