General Information

The Vehicle Theft Deterrent (VTD) system is a function of the Theft Deterrent (VTD) module. When a ignition key is inserted into the ignition lock cylinder, the reader exciter uses wire coils surrounding the ignition lock cylinder to energize a transponder pellet located within the plastic portion of the ignition key. The transponder when energized transmits a unique value by radio frequency back to the reader exciter. The reader exciter sends this value to the VTD module which then validates this value against a value stored in memory and performs one of the following functions:
^ If the value does match the stored value the VTD sends the correct password to the PCM via a class 2 message, the PCM enables fuel delivery to the engine by activating the fuel injectors and the starter relay.

IMPORTANT: The VTD module and PCM operate in conjunction with each other to determine fuel enable. A password is exchanged between the VTD module and PCM when the VTD detects a valid key value over the class 2 serial data line. When the PCM receives a password the PCM validates the password against a password stored in memory and performs one of the following functions:
- If the password matches the PCM enables fuel delivery and activates the starter relay.
- If the password does not match the PCM disables fuel delivery, the starter relay, and sets a DTC.

^ If the value does not match the stored value, the PCM disables fuel delivery to the engine by disabling the fuel injectors, and does not activate the starter relay.