Description And Operation: Description
The RFH module is present in the car's electrical architecture only if the access and ignition keys are Fobik type:
- Car with Fobik key: RFH module present in car.
- Car with mechanical groove key: RFH module not present in car.
Fobik key: RFH functions
- When the car has a Fobik key, the RFH module carries out the following functions:
- Passive Entry
- Key recognition (RFH is part of the Immobilizer system)
Since it has to recognize the keys, their codes are programmed in the RFH module. The ignition switch also comprises a Stop/Start button named KIN module. The button is connected electrically to the RFH module through a LIN line and a connection with an analogue signal called "Redundant Run". This signal permits the RFH to determine whether the Stop/Start button has been pressed if there is a fault on the LIN line.
To carry out the Passive Entry function, the RFH module needs 5 low-frequency peripheral antennas that allow the module to identify and locate the keys.
| Antenna | Location |
|---|---|
| 1 | Rear left door |
| 2 | Rear right door |
| 3 | Rear fascia |
| 4 | Center Console |
| 5 | Tailgate |
The RFH is shown in illustration in connection with the antennas.
The Passive Entry system also makes use of the two door locking buttons on the front handles, through which car users can request door locking. Inside the handles are capacitive sensors (one per handle) which allow the RFH module to determine whether the user's hand is near the inside of the handle.
The RFH module detects the vicinity of the key to the vehicle through antennas. The key recognition and authentication stage begins when the vehicle user brings their hand towards the inside of the handle. At that moment, the RFH reads the key ID and the secret code stored in it. If the RFH module identifies it as the key encoded in its memory, it sends the request to unlock the doors or the driver door only (depending on the setting in the "my car" menu) to the Body Control Module (BCM).