GM Theft Deterrent Systems: VATS, Passlock, Passkey, Passkey II, and Passkey III
Read more for an overview of GM theft deterrent systems and the importance of a relearn procedure.
Theft Deterrent System Functionality and Purpose
The theft deterrent system is designed to prevent vehicle theft by locking down the vehicle when the
ignition or starting system is being tampered with.
Under normal operation, when the key is inserted into the ignition, the ignition lock cylinder sends a signal to the theft deterrent module, or body control module, allowing the vehicle to start.
If the ignition lock cylinder does not detect the correct resistor, magnet, or transponder chip in the key, the vehicle will not start, and the antitheft indicator light will illuminate on the instrument cluster.
After Replacing a Control Module, What is Required to “Relearn” the Key?