Module, Radio Frequency (RF Hub): Operation

The Radio Frequency Hub (RF-Hub) 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.

• Brake Transmission Shift Interlock System (for automatic Transmission only)  - The RF-Hub contains the controlling logic for the Brake Transmission Shift Interlock (BTSI) solenoid. The RF-Hub monitors the key position from the Ignition Node Module (IGNM) received over a private serial bus, hard wires brake input as well as inputs received over the CAN data bus to perform the BTSI solenoid control functions.
• 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  - If Smart door handles or exterior deck lid release switch is activated, RF-Hub activates and monitors Low Frequency (LF) signals from five LF antennas which wake up and communicate with the FOBIK, and Radio Frequency (RF) signals from FOBIK to verify the key, if valid key is recognized by RF-Hub then RF-Hub sends CAN data bus to BCM to lock or unlock the vehicle.
• Remote Keyless Entry  - The RF-Hub is an RF receiver that monitors RF signals from 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 RF-Hub is an RF receiver that 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.
• Sentry Key Immobilizer System  - RF-Hub uses a new high security encryption system called "Advanced Encryption Standard -AES" for Sentry Key Immobilizer System (SKIS). The new system marries FOBIKs, RF-Hub, BCM, ELV (if so equipped" and ECM with unique secret keys for each vehicle. Swapping parts ARE NOT ALLOWED in the new system, FOBIK are not allow to program for more than one Vehicle. Replacing any part of the system shall be done only in an authorized dealers using the proper diagnostic tool.
• Tire Pressure Monitor System  - The RF-Hub is an RF receiver that monitors RF signals received from the Tire Pressure Monitor (TPM) sensors and 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.
• Vehicle Theft Alarm System  - The RF-Hub is an RF receiver that 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 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 switch status. Any input to the RF-Hub 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 RF-Hub to wake up and transmit on the CAN data bus.

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. RF-Hub will also send electronic message requests to the Instrument Cluster (IC) (also known as the Instrument Panel Cluster/IPC) through the gate way module (BCM) for the display of certain textual warning messages related to some detected functions conditions or faults.