Antitheft and Alarm Systems: Description and Operation
ANTI-THEFTAnti-Theft - Passive Anti-Theft System (PATS)
The PATS uses radio frequency identification technology to deter a driveaway theft. Passive means that it does not require any activity from the user.
The PATS uses a specially encoded ignition key. Each PATS key contains a permanently installed electronic device called a transponder. Each transponder contains a unique electronic identification code, with over 18 billion billion combinations.
Each PATS key must be programmed into the vehicle powertrain control module (PCM) before it can be used to start the engine. There are special diagnostic procedures that must be carried out if new PATS keys are to be installed. Refer to General Procedures.
This system contains a feature named Unlimited Key Mode. This feature allows a customer to program more than eight keys to the vehicle if they request it. Each vehicle in Unlimited Key Mode is set up with a special Unlimited Transponder Security Key. This allows all the customer vehicles to share the same keys, but no other keys from outside can be used to operate the vehicles. For an individual customer, any randomly selected Security Key is acceptable. Refer to Key Programming Switch State Control. Switch State Control
The PATS key is larger than a traditional ignition key. The PATS key does not require batteries and should last the life of the vehicle.
The PATS transceiver communicates with the PATS key. The PATS transceiver is located in the steering column attached to the ignition lock cylinder housing. During each vehicle start sequence, the PATS transceiver reads the PATS key identification code and sends the data to the PCM. The PCM validates the code as correct and enables the starter.
The control function is 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 starter enable signal. The PCM initiates the key interrogation sequence when the PATS key is inserted in the ignition switch and when the key is turned to the RUN or START position.
The PCM enables or disables the engine. All elements of 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.
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 will not start
The PATS uses a visual theft indicator, located in the instrument cluster. This indicator proves out for 3 seconds when the key is turned to the RUN or START position under normal operation. If there is a PATS problem, this indicator either flashes rapidly or glows steadily (for more than 3 seconds) when the key is turned to the RUN or START position.
The PATS is not compatible with non-Ford approved aftermarket remote start systems, which allow the vehicle to be started from outside the vehicle. These systems may reduce the vehicle security level, and also may cause no-start issues. Remote start systems must be removed before investigation of PATS-related no-start issues.
The following will activate the PATS and will disable the vehicle from starting:
- incorrectly encoded ignition key
- damaged encoded ignition key
- unprogrammed key
- non-encoded key (key has no electronics)
- damaged wiring
- damaged PATS transceiver
- damaged PCM