Passive Anti-Theft System (PATS) Function: Notes

NOTE: If the IC or the PCM (or both) is replaced, the parameters must be reset in both modules or the vehicle experiences a PATS no-start. Refer to PASSIVE ANTI-THEFT SYSTEM (PATS) PARAMETER RESET .

NOTE: When using the Integrated Diagnostic System (IDS), the IC and the PCM parameters are reset at the same time.

The PATS function is controlled by the IC. PATS uses the IC to carry out all of the PATS functions such as receiving the identification code from the PATS key, sending 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 IC and the PCM, there are parameters that must be set if the IC or the PCM (or both) is replaced. Refer to PASSIVE ANTI-THEFT SYSTEM (PATS) PARAMETER RESET . 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 concerns or IC concerns), the PATS keys must be programmed into the new IC. Refer to INTEGRATED KEYHEAD TRANSMITTER (IKT) KEY PROGRAMMING USING DIAGNOSTIC EQUIPMENT .

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 does not disable a running vehicle.

PATS may cause a vehicle no start due to either the fuel injectors or the starter not operating, or both. Always check for PATS DTCs from the IC and the PCM when a no-crank or no-start condition exists. A low state of charge in the vehicle battery may cause PATS to allow the starter to crank the engine, 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 engine does not crank) 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 IC concern. GO to SYMPTOM CHART .

The PATS function uses the IC and the PCM to enable or disable 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 cannot start. If there is a PATS concern present, the IC sends a message to the PCM to not allow fuel injector operation and also not allow starter operation. If the vehicle starts and stalls, or the engine does not start at all, check the anti-theft indicator operation and if flashing or glowing, retrieve the DTCs from the IC and the PCM and follow the PATS diagnostics in this 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.