GM Service Manual Online
For 1990-2009 cars only

Important: Refer toTheft Deterrent System Check in Body and Accessories if the Passlock Learn Procedure cannot be completed successfully.

Passlock Learn Procedure Using a Tech 2 Scan Tool (Seed and Key)

Important: In addition to the time involved in performing the specific steps, the Seed and Key Procedure accomplishes the same task in 10 minutes as the Auto Learn Procedure does in 30 minutes. Use either one of these two procedures.

The following is the Seed and Key Learn Procedure:

  1. Clear all Vehicle Theft Deterrent (VTD), or (Passlock), module and VCM DTCs.
  2. Turn the ignition to the ON position.
  3. With the scan tool (TECH 2) connected to the vehicle, select "Programming/Request Info" from the menu, then follow the instructions.
  4. Disconnect the scan tool from the vehicle and perform "Service Programming System/VTD Learn" with Techline terminal, then follow the instructions.
  5. Reconnect the scan tool to the vehicle.
  6. Follow the instructions on the scan tool to perform the VTD (Passlock) password learn on the vehicle, this takes about 10 minutes.
  7. After 10 minutes, the SECURITY indicator will turn OFF and the module will learn the new component on the next ignition lock cylinder cycle from OFF-to-CRANK-to-ON (start attempt).

Passlock Learn Procedure without Tech 2 Scan Tool

Important: While the VCM is in the Auto Learn Procedure, maintain the battery voltage at all times. Follow the procedure exactly as indicated or the procedure will have to be repeated from the beginning.

  1. Clear all the VTD (Passlock) module and VCM DTCs.
  2. Turn the ignition switch to the OFF position.
  3. Replace the module or the sensor if necessary.
  4. Turn the ignition switch to the ON position.
  5. Momentarily rotate the ignition switch to the CRANK position. Do not start the vehicle.
  6. Release the ignition switch to the ON position.
  7. Wait 10 minutes. Observe the SECURITY indicator. Refer to the following for the appropriate responses:
  8. • If the Passlock sensor was replaced, the SECURITY indicator will flash for the 10 minute duration.
    • If the VTD (Passlock) module was replaced, the SECURITY indicator will flash for a few seconds and then remain ON for the remainder of the 10 minute duration.
    • If the VCM was replaced with a new VCM off the shelf, the vehicle will start and this procedure may not be necessary.
    • If the replacement VCM was plugged at any other time, even momentarily, the SECURITY indicator will flash for a few seconds and then remain ON for the 10 minute duration.
  9. The SECURITY indicator will make a transition from flashing to ON briefly, then to OFF after 10 minutes if remaining in the ignition ON position.
  10. Turn the ignition switch to the OFF position and wait for 10 seconds.
  11. Repeat steps 3-8 two more times. The module will learn the new component on the next ignition lock cylinder cycle from OFF-to-CRANK-to-ON (start attempt).