Description And Operation: Operation

WARNING: This page is about a different car, the 2022 Chrysler Voyager and 2022 Chrysler Pacifica. However, it is still accessible from the selected car via links, so may be relevant.

The Radio Frequency Hub (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 to support the following standard and optional vehicle features or systems.

Keyless Go Ignition Systems - In backup mode, the KIN communicates with the Frequency Operated Button with Integrated Key (FOBIK) through Low Frequency (LF) signals (125 KHz) then communicates it to RFH through a private serial K bus. The RFH then sends data over the bus to the Body Control Module (BCM) for IGNITION status after a valid key is verified. The RFH also contains the controlling logic for the back lighting features.
Passive Entry - The RFH uses a high security encryption system called "AES" for Passive Entry. If the Smart door handles or exterior release switches are activated, the RFH signals the five Low Frequency (LF) antennas. The LF antenna wakes up the FOBIK then sends the challenge to confirm if it is the correct key, the FOBIK will respond with the Radio Frequency (RF) with the challenge response. When a valid FOBIK 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 - The RFH receives and analyzes RF signals from the Remote Keyless Entry (RKE) transmitter (FOBIK) using an internal antenna, after a valid key is verified, relays the appropriate electronic messages to the BCM module 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 Remote Keyless Entry (RKE) transmitter or the Passive Entry Keyless Go (PEKG) FOBIK; and after a valid key is verified, relays the appropriate electronic messages to BCM over the CAN data bus to support all RKE functions including optional remote start function.
Immobilizer System - RFH uses a high security encryption system called "AES" for Immobilizer System (IS). The system marries FOBIKs, RFH, BCM and Powertrain Control Module (PCM) with unique secret keys for each vehicle. Swapping parts ARE NOT ALLOWED in the new system. Replacing any part of the system shall be done only in authorized dealers using the diagnostic scan tool.
Tire Pressure Monitor System - The RFH is an RF receiver that analyzes RF signals received from the Tire Pressure Monitor (TPM) sensors and then relays the appropriate electronic messages to other electronic modules in the vehicle over the CAN data bus to support the features of the TPM system. The RFH will send a warning if the tire pressure is below or over the set value. When the vehicle is equipped with remote start, the tire pressure signal is received by the remote start antenna.

The RFH is connected to a fused B(+) circuit and has a path to a clean ground at all times. These connections allow it to remain functional regardless of the ignition switch status. Any input to the RFH that controls a vehicle system function that does not require that the ignition switch status be ON such as depressing a button on an RKE or FOBIK transmitter, prompts the RFH to wake up and transmit on the CAN data bus.

RFH uses On-Board Diagnostics (OBD) to monitor all of the Functions and circuits it controls, then sets active and stored Diagnostic Trouble Codes (DTC) for any monitored function faults it detects. RFH will also send electronic message requests to the Instrument Cluster (IC) for the display of certain textual warning messages related to some detected functions conditions or faults.