Anti-Theft - Passive

Anti-Theft - Passive







The passive anti-theft system (PATS) prevents the vehicle from being driven away by an unauthorized persons. The PATS system consists of encrypted electronically coded keys, a transceiver, instrument cluster (IC), and an engine control module (ECM). When the key is inserted into the ignition barrel, the IC uses a decoding process via the transceiver to validate the key transponder code. If the code matches one that is stored and the key is then turned to the run position, the IC will perform a data transfer with the ECM, if valid the ECM will enable the fuel injectors, ignition coils, fuel pump drive and starter.

If the key is invalid the control function will send a theft status message to the ECM, which in turn, will disable the vehicle from starting. If the correct key is used without a transponder or used with a transponder with an incorrect code, the vehicle will be inhibited from starting. This will prevent vehicle theft even if a duplicate key is cut.

A PATS indicator LED (located on the instrument panel) provides the driver with the status of the PATS system. When the ignition is switched to the run position, the PATS indicator LED will illuminate for three seconds and extinguish. If there is a fault with the PATS system after 60 seconds of continuous flashing, the PATS indicator LED will flash an error code.

The best method to confirm the correct operation of PATS is to check the LED (located in the center of the instrument panel). The LED should illuminate solid for 3 seconds when the key is turned to the run position and then extinguish. This validates the PATS functions (the key transponder matches the key code stored, the challenge/response sequence between the instrument cluster (IC) and the engine control module (ECM) was successful resulting in the ECM being enabled).

The ECM will disable the fuel injectors, ignition coils, fuel pump drive and starter if any of the following conditions apply, a theft signal has been received from the IC (the key has not been authenticated), a challenge code has been transmitted to the IC but no response code has been received, a challenge code has been transmitted to the IC and an incorrect response received.

If any of the above cases apply, the ECM will log DTC P1260. This DTC is further defined by sub-codes. The sub-codes are accessed through mode 12 (freeze frame data). Additionally the IC will log DTC's if the failure was a result of the key read.