GM Service Manual Online
For 1990-2009 cars only

Important: Due to component variability, the vehicle theft deterrent (VTD) system must have the learn procedure performed regardless, if the vehicle starts on the first ignition cycle after a VTD repair.

All codes in the theft deterrent module must be cleared for a relearn.

Engineers design the Passlockā„¢ system in order to prevent theft even if the various theft deterrent parts change. The Tamper mode will engage if any of the following components change:

    • The Passlockā„¢ lock cylinder
    • The instrument cluster
    • The powertrain control module (PCM)

If you replace any of the above components, the system will enter the long tamper mode. If the system enters the long tamper mode, ensure that the system completes a long tamper mode cycle. During the long tamper mode cycle, the THEFT indicator will flash for the full 10 minutes. The instrument cluster and the PCM require the full 10 minutes in order to complete the learn cycle. Ensure that the ignition switch remains in RUN until the indicator stops flashing. If you turn the ignition switch before the indicator stops flashing, repeat the long tamper cycle from the beginning.