GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1999 🢒 GMC K Pickup - 4WD 🢒 Body and Accessories 🢒 Theft Deterrent 🢒 PASSLOCK Reprogramming Seed and Key

Disclaimer

This step by step procedure is intended to augment the Passlock™ Diagnostic Repair Procedures. Sole reliance on this procedure may lead to unintended results.

Equipment
    • CD-ROM database containing the passlock seed and key algorithm loaded on a computer with class 2 capability
    • Scan Tool TECH 2 or a compatible scan tool

Conditions

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

The following procedure allows the relearning of the EVO/Passlock™ module or the VCM/PCM learned data code after the replacement of any of the following parts:

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

The EVO/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. If there are any powertrain related DTCs, record those DTCs then:

   • 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

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 Lean procedure does in 30 minutes. Use either one of these two procedures.

The following is the Seed and Key Learn Procedure:

  1. Insure the ignition key is in the ON position.
  2. Clear all EVO/passlock™ module and VCM/PCM DTCs, record those DTCs then:
    3. • 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
  3. With scan tool (TECH 2) connected to the vehicle, select "Programming/Request Info" from menu, then follow instructions.
  4. Disconnect scan tool from vehicle and perform "Service Programming System/VTD Learn" with Techline terminal, then follow instructions.
  5. Reconnect scan tool to the vehicle.
  6. Follow instructions on the scan tool to perform the VTD password learn on the vehicle, this takes about 10 minutes.
  7. After 10 minutes, the SECURITY indicator will turn OFF. The new security code is ready to be communicated among the Passlock sensor, EVO/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).