Module, Radio Frequency (RF Hub): Operation

WARNING: This page is about a different car, the 2020 Dodge Challenger. However, it is still accessible from the selected car via links, so may be relevant.

The Radio Frequency Hub (RF-Hub) is an integrated receiver in the vehicle that communicates with other Electronic Control Modules (ECUs) 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 - The Keyless Ignition Node (KIN) communicates with the FOBIK's through Low Frequency (LF) signals (125 KHz) then communicates those signals to the RF-Hub through a private serial bus, then the RF-Hub sends CAN data bus messages to the Body Control Module (BCM) for IGNITION status after valid key is verified. The RF-Hub also contains the controlling logic for the backlighting features.
Passive Entry (PE) - If the Smart door handles or exterior deck lid release switch are activated, the RF-Hub signals and monitors the five LF antennas. The LF antennas send out RF signals to the Finger Operated Button Ignition Key (FOBIK) to verify the FOBIKs validity. When a valid FOBIK is recognized by the RF-Hub a CAN data bus message is sent to BCM to lock or unlock the vehicle by the RF-Hub
Remote Keyless Entry (RKE) - The RF-Hub receives and monitors RF signals from the RKE transmitter FOBIK; and relays the appropriate electronic messages to the BCM over the CAN data bus to support the features of RKE functions.
Remote Start System - The RF-Hub receives and monitors RF signals received through the Remote Start Antenna (RSA) (longer range) from the RKE transmitter FOBIK or the PE Keyless Go (PEKG) FOBIK and relays the appropriate electronic messages to BCM over the CAN data bus to support all RKE functions including the optional remote start function.
Sentry Key Immobilizer System (SKIM) - The RF-Hub uses a high security encryption system called "HITAG" for the SKIM. The SKIM system marries the FOBIKs, RF-Hub and the ECM with unique secret keys for each vehicle. Swapping parts ARE NOT ALLOWED in this system. Replacing any part of this system shall be done only in authorize dealers using the diagnostic scan tool.
Vehicle Theft Alarm (VTA) System - The RF-Hub receives and monitors RF signals received from the RKE transmitter or the PEKG FOBIK and relays the appropriate electronic messages to other ECUs in the vehicle over the CAN data bus to support the features of the optional VTA system.

The RF-Hub 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 status. Any input to the RF-Hub that controls a vehicle system function that does not require that the ignition status be ON such as depressing a button on an RKE or FOBIK transmitter prompts the RF-Hub to wake up and transmit on the CAN data bus.

The RF-Hub 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. The RF-Hub will also send electronic message requests to the Instrument Panel Cluster (IPC) through the BCM for the display of certain textual warning messages related to some detected function conditions or faults.