PATS Operation

WARNING: This page is about a different car, the 2007 Ford Ranger. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: If the instrument cluster or the PCM is being replaced (or both), the parameters must be reset in both modules or the vehicle will experience a PATS no-start. This will occur even if the vehicle is not equipped with PATS. PATS vehicles and non-PATS vehicles have parameters in the instrument cluster and the PCM and they must be reset whenever either (or both) module(s) is (are) replaced. Refer to Passive Anti-Theft System (PATS) Parameter Reset in this article.

The PATS function is controlled by the instrument cluster. With this type of PATS, there are parameters that will need to be reset if either the instrument cluster or the PCM (or both) are replaced. Refer to PATS Parameter Identification (PIDs). When the PATS key is turned to the ON or START position, the instrument cluster 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 instrument cluster, 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 instrument cluster 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 instrument cluster 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 instrument cluster will flash (or may glow steadily) and the instrument cluster will store one or more diagnostic trouble codes (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 instrument cluster must be replaced for any reason (PATS concerns or driveability concerns), the PATS keys must also be programmed into the new instrument cluster. Refer to Key Programming Using Diagnostic Equipment in this article.