Anti-Theft - Passive Anti-Theft System (PATS)

Anti-Theft

The Passive Anti-Theft System (PATS) consists of the following components:

- Anti-theft indicator (located in the light sensor)
- Encoded (the key contains a transponder) PATS ignition key(s)
- PATS transceiver
- PCM

PATS uses radio frequency identification technology to deter a drive-away theft. Passive means that it does not require any activity by the user.

The vehicle is equipped with 2 PATS keys and 1 valet PATS key. A maximum of 8 PATS keys can be programmed to start the vehicle. If additional PATS keys are desired, refer to Spare Key Programming - Unlimited Key Mode Unlimited Key Mode.

Passive Anti-Theft System (PATS) Function

The PATS function is controlled by the PCM. PATS uses the PCM to carry out all of the PATS functions such as receiving the identification code from the PATS key, controlling the starter and fuel injectors enable, and initiating the key interrogation sequence when the ignition key is turned to the ON or START position. 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 PCM must be replaced for any reason (PATS concerns or driveability concerns), the PATS keys must be programmed into the new PCM. Refer to Key Programming Using Diagnostic Equipment 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 cannot disable a running vehicle.

PATS is not compatible with aftermarket remote start systems, which allow the vehicle to be started from the exterior of the vehicle. These systems can reduce the security of the vehicle, and also can 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.

A PATS no-start can involve a vehicle no-start due to either the fuel injectors not operating or the starter not operating (starter relay does not close) or both. Always check for PATS DTCs from the PCM when a no-crank or no-start condition exists. A low state of charge in the vehicle battery can cause the PATS to allow starter operation, but prevent the fuel injectors from operating. If the PATS 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 can be due to a PATS concern. If the anti-theft indicator proves out, and the vehicle does not start, it is probably not a PATS concern. Refer to Computers and Control Systems Information. If the anti-theft indicator does not illuminate at all, it can be a circuitry/light sensor/PCM concern. GO to Symptom Chart. Symptom Related Diagnostic Procedures

PATS disables the vehicle from starting if there is:

- a damaged PATS key.
- an unprogrammed PATS key.
- a non-encoded key (a conventional key or one that does not have any electronics).
- damaged wiring.
- a damaged transceiver.
- a damaged PCM.

Unlimited Key Mode

PATS contains a feature called unlimited key mode. This feature allows a customer to program more than 8 vehicle keys, if requested. Each vehicle in unlimited key mode is set up with a special, unlimited transponder security key code. This allows all the customer vehicles to share the same mechanically cut keys (more than 8 keys). For an individual customer, any randomly selected security key that has been previously mechanically cut and electronically programmed to the vehicle is acceptable. Refer to Spare Key Programming - Unlimited Key Mode Unlimited Key Mode.