GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1999 🢒 Savana 🢒 Body and Accessories 🢒 Theft Deterrent 🢒 PASSLOCK Reprogramming Auto Learn

Conditions

Important: If a new vehicle/powertrain control module (VCM/PCM) is being installed for the first the manufacturing enable bit will be set and the auto learn procedure may not be necessary.

The following procedure allows for anyone to reprogram the Passlock™ module learned data code with any tools, other than the scan tool, when any of the following parts are replaced:

    • The Passlock™ module
    • The passlock™ sensor
    • The VCM/PCM

The Passlock™ module will set the DTC B3031 module in the learn mode when entering the reprogramming procedure.

Steps

Important: Erase the passlock™ related diagnostic trouble codes (DTCs) that are stored in the VCM/PCM. Record, then refer these DTCs to:

   • For 4.3L engines, refer to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls - 4.3L
   • For 5.0/5.7L engines, refer to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls - 5.0/5.7L
   • For 6.5L engines, refer to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls - 6.5L
   • For 7.4L engines, refer to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls - 7.4L

The following is the Auto Learn Procedure:

  1. Insure the ignition key is in the ON position.
  2. Insure all passlock™ module and VCM/PCM DTCs have been cleared.
  3. Momentarily rotate the ignition key to the CRANK position (Do NOT start the vehicle), then release it to the RUN position (Do NOT key OFF in the process).
  4. Wait 10 minutes. Observe the SECURITY indicator. Refer to the following list for the appropriate responses:
    5. • If the passlock™ sensor was replaced the SECURITY indicator will flash for the 10 minutes duration.
    • If the passlock™ module was replaced, the SECURITY indicator will flash for a few seconds and then remain ON for the remainder of the 10 minutes duration.
    • If the VCM/PCM was replaced with a new programmed VCM/PCM and connected to the vehicle for the first time, the vehicle will start and this procedure may not be necessary.
    • If the replacement VCM/PCM was connected to any vehicle at any other time, even momentarily, the SECURITY indicator will flash for a few seconds and then remain ON for the 10 minutes duration.
  5. The SECURITY indicator will transition from flashing to ON briefly to OFF after 10 minutes if remaining in the ignition ON position.
  6. Turn the ignition switch to the OFF position and wait for 10 seconds.
  7. Repeat steps 3-6 two more times. The new security code is ready to be communicated among the Passlock sensor, Passlock module and VCM/PCM. The new password is learned on the next ignition lock cylinder cycle from OFF to CRANK to ON (start attempt).