Description And Operation: Operation

The Radio Frequency Hub (RFH) is an integrated receiver 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 start stop button communicates with the Frequency Operated Button Integrated Key (FOBIK) through LF signals 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.
• Passive Entry  - If the Smart door handles or exterior deck lid release switch are activated, the RFH signals and monitors the three 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 to the BCM to support the features of RKE functions, allowing the vehicle to be locked or unlocked when the button on the FOBIK are pressed, when the FOBIK is with in range.
• Sentry Key Immobilizer System  - The RFH sentry key immobilizer system only allows Remote Keyless Entry (RKE) transmitters that have been previously programmed to the vehicle to start the engine.
• Steering Lock Mechanism  - The steering lock mechanism is integrated into the RFH, and directly controls steering locking and unlocking the steering by inserting and withdrawing the steering lock pin. The steering lock mechanism must be unlocked before the RFH is to be removed, failure to do so will result in the inability to remove the RFH. If the start button indicator light (green) is flashing and the audible beep sound is heard, this indicates that the steering lock is not released. To unlock the steering wheel, press the start button while moving the steering wheel left and right.
• Tire Pressure Monitor  - The RFH receives data from the keyless entry receiver, that were received from the TPM sensors, and then relays the appropriate electronic messages to other electronic modules in the vehicle to support the features of the TPM system. The RFHM will send a warning if the tire pressure is below the set value to the Instrument Panel Cluster (IPC) to illuminate the warning light and will also provide an audible chime. For further information on the TPM. Refer to TIRE PRESSURE MONITORING, DESCRIPTION AND OPERATION .

The RFH also receives signals from the switches (wiper and washer switch, light switch, steering switch, etc.) near the RFH, and sends them to the relative modules.

If the RFH is replaced the following will need to be completed: Configuration, key programming, and key ID clearing. Refer to MODULE, RADIO FREQUENCY (RF HUB), MODULE PROGRAMMING . Another routine located in the Powertrain Control Module (PCM) "Miscellaneous Functions" menu called "PCM/RFH Replace" will need to be performed.

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.