General Information

The vehicle VTD functions are provided by the Pass Key III(R) system. Pass Key III (R) consists of an ignition key with a transponder embedded in the head, the VTD Controller Module, the exciter assembly, and the PCM.

The exciter assembly is an antenna which is made up of wire coils which surround the ignition lock cylinder. These coils, powered by the VTD Controller Module, emit electromagnetic energy which energizes the transponder pellet within the head of the key. The energized transponder transmits a unique value by radio frequency which is detected by the exciter. The VTD Controller Module receives and compares this value to one stored in memory (a learned value). If the received transponder value matches a learned value, the VTD Controller Module sends a password via the class 2 serial data line to the PCM. The PCM compares this password to one stored in memory (a learned password). If the passwords match the PCM enables engine starting.

This password is unique for each VTD Controller Module along with the unique value of the key's transponder. This method prevents swapping one of the following modules in order to start the vehicle:
^ The VTD Controller Module - which must receive the unique key value and then sends a unique password.
^ The PCM - which must receive the correct password from the VTD Controller Module to enable engine starting.