Antitheft and Alarm Systems: Description and Operation

The Passive Anti-Theft System (PATS) Components:

The Passive Anti-theft System (PATS) also contains the following components:
^ Theft indicator.
^ Encoded ignition key.
^ Passive anti-theft transceiver module.
^ Hybrid Electronic Cluster (HEC).
^ Powertrain control module.
^ J1850 communication network.
^ Lighting Control Module (LCM).

The passive anti-theft system (PATS) uses radio frequency identification technology to deter a driveaway theft. Passive means that it does not require any activity from the user. This system is known as SecuriLock(R) in North America, Safeguard(R) in the U.K., and PATS in Continental Europe. This information can be found in customer literature such as the Owner's Manual.

PATS uses a specially encoded ignition key. Each encoded ignition key contains a permanently installed electronic device called a transponder. Each transponder contains a unique electronic identification code out of over 72 million billion combinations.

Each encoded ignition key must be programmed into a vehicle's Hybrid Electronic Cluster (HEC) before it can be used to start the engine. There are special diagnostic service procedures that must be performed if the encoded ignition keys need to be replaced.

The encoded key is larger than a traditional ignition key. The key does not require batteries and should last the life of the vehicle.

The transceiver module communicates with the encoded ignition key. This module is located behind the steering column shroud, and contains an antenna connected to a small electronic module. During each vehicle start sequence, the transceiver module reads the encoded ignition key identification code and sends the data to the HEC.

The control functions are contained in the HEC. This module performs all of the PATS functions, such as receiving the identification code from the encoded ignition key and controlling engine enable. The HEC initiates the key interrogation sequence when the vehicle ignition switch is turned to RUN or START.