Description & Operation

WARNING: This page is about a different car, the 2002 Lincoln Navigator, 2002 Ford Expedition, 2001 Lincoln Navigator, and 2001 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.

WARNING: Vehicles are equipped with air bag supplemental restraint system. Before attempting ANY repairs involving steering column, instrument panel or related components, see AIR BAG SAFETY PRECAUTIONS and DISABLING & ACTIVATING AIR BAG SYSTEM in appropriate AIR BAG RESTRAINT SYSTEMS article in RESTRAINTS.

NOTE: This system is not compatible with non-factory remote start systems, which allow vehicle to be started from outside by driver. Remote system must be removed before any diagnosis or repairs are made to passive anti-theft system related no-start issues. All elements of passive anti-theft system must be functional or vehicle will not start.

Passive Anti-Theft System (PATS) uses a theft indicator, encoded ignition key, transceiver module, Powertrain Control Module (PCM), standard corporate protocol communication network and PCM power and start interrupt relays. PATS uses radio frequency identification technology to deter driveaway theft. Passive means it does not require any activity from user. PATS uses specially encoded keys containing permanently installed transponders. Each transponder contains an identification code. Each replacement encoded ignition key must be programmed into instrument cluster before it is able to start engine. Encoded keys are larger than traditional keys, do not require batteries and should last lifetime of vehicle.

PATS transceiver module communicates with encoded ignition key. During each vehicle start sequence, transceiver module reads encoded identification code and sends data to PCM. PCM initiates key interrogation sequence when vehicle ignition switch is turned to ON or START position. PATS uses PCM to enable or disable engine.

Theft indicator will prove out for 3 seconds when ignition switch is turned to ON or START position. If PATS is malfunctioning, theft indicator will flash rapidly or glow steadily. PATS theft indicator flashes every 2 seconds after ignition switch is turned to OFF position to act as a visual deterrent. PATS will not store DTCs or flash theft indicator if valid encoded ignition key is used and a failure occurs in starter relay circuit.

An unlimited key mode system is featured to allow programming of more than 8 keys to vehicle if needed. Each vehicle in unlimited key mode is set up with a special unlimited transponder security key. This allows all customer vehicles to share same keys, but no other keys from outside can be used to operate vehicles. For an individual customer, any randomly selected security key is acceptable.