Normal Operation
During each vehicle start sequence, when the start/stop switch is pressed, the Remote Function Actuator (RFA) activates all 3 passive start antennas, which send out a low frequency signal. If an Intelligent Access (IA) key is within range of an passive start antenna, the low frequency signal activates the IA key. When the IA key is activated it sends a high frequency signal to the Remote Functions Receiver (RFR) module. The RFR module communicates with the RFA module. If the RFA module determines that a programmed IA key is in the vehicle, it interacts with the PCM to start the vehicle.
If the vehicle has a failure of any passive start antenna, the battery in the IA key, or the RFR module, the vehicle can experience a Passive Anti-Theft System (PATS) no-start. However, in the event of one of these failures, the IA key can be placed in the backup slot (located in the center console) to allow the vehicle to start. The backup transceiver is located next to the backup slot and activates an IA key if it is placed in the slot. The backup transceiver is hardwired to the RFA module and when it is activated, sends out a low frequency signal. If a programmed IA key is in the backup slot when the backup transceiver is activated, it activates the IA key and the identification code is sent back to the RFA module through the backup transceiver.
Once the RFA module determines that a programmed IA key is inside the vehicle and receives a request to start the engine, it turns the ignition ON and communicates with the PCM over the High Speed Controller Area Network (HS-CAN). Once the ignition mode is turned ON, both the RFA module and PCM check the parameters against what has been programmed into them. If there is a programmed IA key inside the vehicle and the parameters are correct, then the RFA module and PCM enable the starter relay and fuel injectors.