Important: If a new vehicle control module (VCM) 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 will set the DTC B3031 module in the learn mode when entering the reprogramming procedure.

Important: Erase the passlock™ related diagnostic trouble codes (DTCs) that are stored in the VCM. If there are any powertrain related DTCs, record these DTCs and refer to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls - 4.3L

The following is the Auto Learn Procedure:

1. Insure the ignition key is in the ON position.
2. Clear all passlock™ module and VCM DTCs. Record and refer any VCM DTCs to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls - 4.3L
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:

•	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 was replaced with a new programmed VCM and connected to the vehicle for the first time, the vehicle will start and this procedure may not be necessary.

•	If the replacement VCM 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. The new password is learned on the next ignition lock cylinder cycle from OFF to CRANK to ON (start attempt).