Description And Operation
DESCRIPTION
The Radio Frequency Hub (RFH) (1) is located behind the left rear retractor trim panel. The RFH:
- is secured in place with two screws
- can have either two or three connections: a pink coaxial connector for remote start only, a 16 way connector, and a 20 way connector.
The RFH is an integrated receiver (base station) in the vehicle that interfaces with the key fob using both Radio Frequency (RF) and Low Frequency (LF) signals.
This model RFH has two connector receptacles integral to the RFH housing and are connected to the vehicle electrical system through dedicated take outs and connectors of the body wire harness. A remote start antenna is connected directly to the RFH through a third integral connector receptacle.
OPERATION
The RFH is an integrated receiver (or base station) in the vehicle that communicates with other electronic modules in the vehicle over either the Controller Area Network (CAN) data bus or a private serial bus. The RFH is also hard wired to the vehicle's door handles and multiple LF antennas. Using the data bus network and the hard wired signals, the RFH supports the following standard and optional vehicle features:
- Keyless Go Ignition Systems - In backup mode, the Keyless Ignition Node (KIN) communicates with the key fob through LF signals (125 KHz) then communicates the key fob information to RFH through a private serial K bus. The RFH then sends ignition status data over the bus to the Body Control Module (BCM) after a valid key fob is verified. The RFH also contains the controlling logic for the back lighting features of the KIN.
- The RFH will, at a minimum, receive the following information from the KIN:
- START/STOP button states
- Transponder authentication in back up mode
The RFH will, at a minimum, transmit the following information to the KIN:
- START/STOP button backlighting control
- Ignition status ring back lighting control
- Immobilizer System - RFH uses a high security encryption system called Advanced Encryption Standard (AES) for the Immobilizer System. The RFH marries itself to the BCM and Powertrain Control Module (PCM) with AES at first ignition ON in the assembly plant. Then the system marries the key fobs, RFH, BCM and the PCM with unique secret keys for each vehicle. Swapping any of the married parts ARE NOT ALLOWED in the new system.
- Passive Entry (PE) - The RFH also uses AES for PE operation. If the Smart door handles or exterior release switches are activated, the RFH signals the LF antennas. The LF antenna wakes up the key fob then sends a challenge to confirm if it is the correct key fob. Then the key fob will respond to the RFH with the challenge response. When a valid key fob is recognized by the RFH, a CAN data bus message is sent to BCM to lock or unlock the vehicle by the RFH.
- Remote Keyless Entry (RKE) - The RFH receives and analyzes RF signals from the key fob; and after a valid key fob is verified, relays the appropriate electronic messages to the BCM over the CAN data bus to support the features of RKE functions.
- Remote Start System - The RFH receives and analyzes RF signals received through the remote start antenna (longer range) from the key fob; and after a valid key fob is verified, relays the appropriate electronic messages to BCM over the CAN data bus to support all RKE functions including optional remote start function.