GM Service Manual Online
For 1990-2009 cars only

Engineers design the Passlock™ system in order to prevent the theft of the vehicle. Passlock™ disables the engine unless a mechanical key engages the Passlock™ lock cylinder. The system is similar in concept to the Pass-Key® System. Passlock™ eliminates the need for a key mounted resistor pellet. The system contains the following components:

    â€¢ The Passlockâ„¢ lock cylinder
    â€¢ The ignition switch
    â€¢ The instrument cluster
    â€¢ The powertrain control module (PCM)