Passive Anti-Theft System (PATS) Operation

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 communicate with 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  sends a message to the PCM to ground the starter relay solenoid coil and 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  sends 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  flashes (or may glow steadily) and the IC  stores one or more DTCs.

All elements of PATS  must be functional before the vehicle starts. If any of the components are not working correctly, the vehicle cannot start. If the IC  must be replaced for any reason(PATS  or IC  concerns), the PATS keys must also be programmed into the new IC  . Refer to 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  .
• a damaged PCM.