PATS Operation

WARNING: This page is about a different car, the 2009 Mercury Sable, 2009 Ford Taurus X, and 2009 Ford Taurus. However, it is still accessible from the selected car via links, so may be relevant.

The PATS function is controlled by the IC. With this type of PATS, there are parameters that need to be reset if either the IC or the PCM (or both) are replaced. Refer to Passive Anti-Theft System (PATS) Parameter Reset .

When the PATS key is turned to the ON or START position, the IC initiates the key interrogation sequence by sending a voltage signal to the PATS transceiver. The transceiver then uses its antenna to bounce a signal off the transponder in the PATS key. This process "reads" the PATS key identification code and sends the key identification code back to the IC, which interprets it and determines if it matches one of the stored key codes. If it does match one of the stored key codes, the IC will send a message to the PCM to ground the starter relay solenoid coil and to also allow the fuel injectors to operate. If it does not match one of the stored key codes, or it is only a partial key read or no key read, the IC will send a message to the PCM to not ground the starter relay solenoid coil and not allow fuel injector operation. The anti-theft indicator in the IC will flash (or may glow steadily) and the IC will store one or more DTCs.

All elements of PATS must be functional before the vehicle will start. If any of the components are not working correctly, the vehicle will not start.

If the IC must be replaced for any reason (PATS concerns or IC concerns), the PATS keys must also be programmed into the new IC. Refer to Integrated Keyhead Transmitter (IKT) Key Programming Using Diagnostic Equipment .

PATS disables the vehicle from starting if there is:

a damaged PATS key.
a non-programmed PATS key.
a non-PATS key (key has no electronics).
damaged wiring.
a damaged transceiver.
a damaged IC.