Principles of Operation

PASSIVE ANTI-THEFT SYSTEM (PATS) - PRINCIPLES OF OPERATION

The PATS uses radio frequency identification technology to deter a driveway theft. Passive means that it does not require any unique activity to operate the system.

The PATS uses a special PATS key. Each PATS key contains a permanently installed electronic device called a transponder. Each transponder contains a unique electronic identification code which is one of many combinations.

Each PATS key must be programmed into the vehicle's powertrain control module (PCM) before the key can be used to start the engine. There are special diagnostic repair procedures outlined that must be carried out if a new PATS key is necessary.

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

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

All elements of the PATS must be functional before the engine is allowed to start. If any of the components are not working correctly, the vehicle does not start.

The PATS uses a visual theft indicator located in the instrument cluster. The indicator proves out for 3 seconds when the ignition lock cylinder is turned to RUN or START under normal operation. If there is a PATS problem, this indicator either flashes rapidly or glows steadily when the ignition lock cylinder is turned to RUN or START. The PATS system also flashes the theft indicator every 2 seconds at ignition OFF to act as a visual deterrent.

The PATS disables the vehicle from starting if there is a:
- damaged PATS key
- unprogrammed PATS key
- non-PATS key (key has no electronics)
- damaged wiring
- damaged PATS transceiver
- damaged powertrain control module (PCM)