Module, Radio Frequency (RF Hub): Operation

WARNING: This page is about a different car, the 2017 Dodge Charger. 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 - The Keyless Ignition Node (KIN) communicates with the Frequency Operated Button Integrated Key (FOBIK) through LF signals (125 KHz) then communicates it to RFH through a private serial bus, then RFH sends CAN data bus to the Body Control Module (BCM) for IGNITION status after valid key is verified. The RFH also contains the controlling logic for the back lighting features.
Passive Entry - If the Smart door handles or exterior deck lid release switch are activated, the RFH signals and monitors the five Low Frequency (LF) antennas. The LF antennas send out Radio Frequency (RF) signals to the FOBIK to verify the FOBIK. 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 monitors RF signals from the Remote Keyless Entry (RKE) transmitter (FOBIK); and relays the appropriate electronic messages BCM module over the CAN data bus to support the features of RKE functions.
Remote Start System - The RFH receives and monitors 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 relays the appropriate electronic messages to BCM over the CAN data bus to support all RKE functions including optional remote start function.
Secure Park Feature - Charger Pursuit vehicles also have a unique Secure Park feature that will prevent the transmission gear selector of a vehicle left idling from being shifted out of Park (P) or moving more than about 0.9 meters (3 feet) if there is no valid FOB with Integrated Key (FOBIK) detected within the interior of the vehicle. This feature can be enabled using a diagnostic scan tool. Once enabled, it is activated or deactivated by depressing the center remote radio button on the back of the steering wheel. While this feature is passive and does prevent vehicle theft, it actually relies primarily upon features of the Keyless Go (KG) portion of the Passive Entry Keyless Go (PEKG) system, which is discussed in further detail elsewhere within this service information
Sentry Key Immobilizer System - RFH uses a high security encryption system called "HITAG" for Sentry Key Immobilizer System (SKIM). The system marries FOBIKs, RFH and ECM 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 an authorized dealer using the proper diagnostic scan tool.
Vehicle Theft Alarm System - The RFH receives and monitors RF signals received from the Remote Keyless Entry (RKE) transmitter or the Passive Entry Keyless Go (PEKG) FOB with Integrated Key (FOBIK); and relays the appropriate electronic messages to other electronic modules in the vehicle over the CAN data bus to support the features of the optional Vehicle Theft Alarm (VTA) system.

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) through the BCM for the display of certain textual warning messages related to some detected functions conditions or faults.

The hard wired inputs and outputs of the RFH may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the RFH electronic controls or the communication between modules and other devices that provide some features of the RFH-controlled systems. The most reliable, efficient and accurate means to diagnose the RFH or the electronic controls and communication related to RFH-controlled systems operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.