LEMON Manuals: Even more car manuals for everyone
Home >> Mercedes Benz >> 2011 >> GL350 >> Repair and Diagnosis >> Electrical >> Motors, Switches, Relays >> Electrical System, Equipment & Instructions - 164 Chassis - 2 Of 4 >> Basic Knowledge >> Backup camera (RFK), function >> Backup camera (RFK), function - GF54.65-P-0005GZJ

Backup camera (RFK), function - GF54.65-P-0005GZJ

MODEL 164 with CODE (218) Backup camera with CODE (498) Japan version except CODE (849) Spare wheel holder/spare wheel up to Model Year 2008 

MODEL 251 with CODE (218) Backup camera with CODE (498) Japan version up to Model Year 2008 

Fig 1: Backup Camera Communication Diagram
G10117087Courtesy of MERCEDES-BENZ USA

Complete description of backup camera system (RFK) 

The backup camera system (RFK) assists the driver when parking and when backing up. With the aid of the backup camera in the rear-end door and the passenger-side outside mirror backup camera, the entire surrounding area to the rear of the vehicle and events in the area below the front passenger mirror are displayed on the COMAND operating, display and controller unit in NTSC format via the backup camera control unit.

IMPORTANT External environmental influences such as darkness, dust, fog or precipitation can however restrict the functionality of the backup camera and passenger-side outside mirror backup camera.

The backup camera control unit is the central controller unit in the backup camera system (RFK). It transmits the real-life video pictures from the backup camera and passenger-side outside mirror backup camera directly to the display of the COMAND operating, display and controller unit. The backup camera control unit superimposes virtual guide lines and warning messages over these real-life video images, which provide the user with more detailed information on events in the area at the rear of the vehicle.

If both cameras are activated, they are supplied with voltage by the backup camera control unit. Both cameras transmit pictures to the backup camera control unit over discrete lines as CVBS signals.

IMPORTANT The abbreviation CVBS signal stands for Composite Video Baseband Signal, which is the English language equivalent of the German analog FBAS signal (Farb-Bild-Austast-Synchron-Signal).

The video signals from both cameras and the superimposed video pictures are transmitted to the COMAND operating, display and controller unit using the NTSC standard.

Function requirements 

The backup camera system (RFK) lets the driver choose between two park modes using the softkeys in the COMAND operating, display and controller unit (A40/3).

  1. Back-in parking mode (back-in parking)
  2. Parallel parking mode (parallel parking)

When reverse gear is engaged, back-in parking mode is activated as standard. Parallel parking mode can be activated additionally at any time via the COMAND operating, display and controller unit.

IMPORTANT The electric signals generated by the driver through the DIRECT SELECT gear selector switch for transmission position "R" are transferred by the steering column module (N80) to the intelligent servo module for DIRECT SELECT via CAN C. The intelligent servo module for DIRECT SELECT (A80) then transfers the message "Reverse gear engaged" to the central gateway control unit via CAN C and from there to the backup camera control unit via CAN B.

Function restrictions 

The backup camera in the rear-end door must be calibrated before the system functions optimally. This takes place with the rear-end door closed. If the backup camera control unit receives the signal "Rear-end door OPEN" from the rear SAM control unit via CAN B, it removes the guide lines. Only the current camera picture is then displayed in the COMAND operating, display and controller unit.

A trailer does not affect the function of the backup camera control unit. All of the guide lines calculated using the vehicle data continue to be displayed on the COMAND operating, display and controller unit.

Driver termination of backup camera system 

If the backup camera system is terminated, the backup camera control unit internally stores the last park function activated.

Termination of backup camera system by backup camera control unit 

If a system malfunction occurs

(e.g. backup camera in rear-end door fails), the backup camera control unit terminates the system independently and places a corresponding fault message in the internal fault memory.

  Backup camera (RFK) location of components Model 164 GF54.65-P-0005-01GZJ
Model 251 GF54.65-P-0005-01RTJ
  Backup camera (RFK), block diagram   GF54.65-P-0005-02GZJ
  Back-in parking, function   GF54.65-P-2005GZJ 
  Parallel parking, function   GF54.65-P-2006GZJ