Passive Anti-Theft System (PATS) Function

The PATS function is controlled by the IPC. The PATS uses the IPC to carry out all of the PATS functions such as receiving the identification code from the PATS key, issuing a signal to the PCM to control the starter and fuel injectors enable, and initiating the key interrogation sequence when the ignition key is turned to the ON or START position. Because of the interaction between the IPC and the PCM, there are parameters that must be set if the IPC or the PCM (or both) are replaced. Refer to PASSIVE ANTI-THEFT SYSTEM (PATS) PARAMETER RESET  in this service information. If the IPC must be replaced for any reason (PATS concerns or an IPC concern), the PATS keys also must be programmed into the new IPC. Refer to INTEGRATED KEYHEAD TRANSMITTER (IKT) KEY PROGRAMMING USING DIAGNOSTIC EQUIPMENT  in this service information. All elements of PATS must be functional before the vehicle starts. If any of the components are not working correctly, the vehicle does not start.

PATS is active only for a few seconds when the vehicle is starting. It is not a PATS concern if the vehicle stalls after it has been running for a minimum of 3 seconds. PATS cannot disable a running vehicle.

PATS may cause a vehicle no start due to either the fuel injectors or the starter not operating (starter relay does not close) or both. Always check for PATS DTCs from the IPC and DTCs from the PCM when a no-crank or no-start condition exists. A low state of charge in the vehicle battery may cause the PATS to allow starter operation, but prevent the fuel injectors from operating.

If the anti-theft indicator does not prove out (it may be either flashing or glowing steadily) and one (or both) of the previous conditions (fuel injectors and/or starter inoperative) are present, it may be due to a PATS concern. If the anti-theft indicator proves out, it may not be a PATS concern. If the anti-theft indicator does not illuminate at all, it may be an IPC concern. Refer to the SYMPTOM CHART  in this service information.

PATS is not compatible with aftermarket remote start systems, which allow the vehicle to be started from the exterior of the vehicle. These systems may reduce the security of the vehicle, and also may be the cause of no-start concerns. Remote start systems must be removed from the vehicle before any PATS-related no-start concerns are investigated.