Circuit Operation

PASS-Key(R) II Vehicle Theft Deterrent (VTD) allows the vehicle to start only when the resistance pellet of the ignition key is recognized by the body control module (BCM). If an incorrect resistance value is seen by the BCM, the engine is prevented from starting in two ways:
^ Battery voltage is disabled through the starter relay to the starter solenoid.
^ The fuel injectors are disabled by the powertrain control module (PCM).

On vehicles equipped with VTD, the BCM will initiate an audible alarm cycle if an attempt is made to start the vehicle with an incorrect ignition key. Voltage is applied to the BCM through circuit 39 when the ignition key is inserted into the ignition lock cylinder and turned to the START position. The BCM checks the pellet resistance of the ignition key through circuit 1073, through circuit 1074, and the ignition key lock cylinder. If the resistance is correct, the BCM applies ground through circuit 625 to the starter relay coil. At the same time, the BCM applies a fuel enable signal through circuit 229 to the powertrain control module (PCM). The PCM allows the vehicle to start and run and then tests circuit 229. If the fuel enable signal is present from the BCM, the engine continues to run. If the signal is not present, the PCM disables the fuel injectors, and the engine stops.

If the resistor pellet has the wrong resistance value, the BCM disables vehicle starting for approximately 3 minutes. The starter relay and the fuel injectors are disabled. After the 3 minute period the vehicle can be started with the correct ignition key.