Backup camera (RFK), function - GF54.65-P-0005GZ
MODEL 164 with CODE (218) Backup camera with CODE (494) USA version except CODE (849) Spare wheel holder/spare wheel
MODEL 251 with CODE (218) Backup camera with CODE (494) USA version
Data flow chart shown on model designation 164
Data flow chart shown on model designation 251
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, the entire surrounding area to the rear of the vehicle is displayed in CVBS format on the display of the COMAND operating, display and controller unit. At the same time as the video is displayed on the screen, warnings appear which urge the driver not to neglect actual events in the area surrounding the vehicle.
If the driver assist system is activated, the backup camera voltage supply module supplies voltage to the backup camera in the rear-end door.
The backup camera then transmits an analog video picture back to the backup camera voltage supply component.
The backup camera voltage supply module loops the video signal through and transfers the video picture to the operating, display and controller unit over a screened coaxial line.
CVBS stands for Composite Video Base-band Signal. This is an analog video signal, which combines all relevant information (e.g. color and brightness values etc.) in just one signal.
External environmental influences such as darkness, dust, fog or precipitation can however restrict the functionality of the backup camera.
System components
- COMAND operating, display and control unit
- Voltage supply module, backup camera
- Backup camera in rear-end door
Function requirements
- Circuit 15 ON
- Reverse gear engaged (selector lever position "R") via DIRECT SELECT gear selector switch (S16/13)
- COMAND operating, display and controller unit activated.
Activation of COMAND operating, display and control unit
The COMAND operating, display and controller unit shows the video pictures from the backup camera in the display as soon as it receives the digital signal "Reverse gear engaged" via CAN B.
The electric signals generated by the driver through the DIRECT SELECT gear selector switch for transmission position "R" are transferred from the steering column module (N80) to the intelligent servo module for DIRECT SELECT via CAN C.
The intelligent servo module for DIRECT SELECT then transfers the message "Reverse gear engaged" to the central gateway control unit via CAN C and from there to the COMAND operating, display and controller unit via CAN B.
Voltage supply module, backup camera
The backup camera voltage supply module supplies voltage to the backup camera and transfers the video pictures to the COMAND operating, display and controller unit over a discrete line. The basis for activation of the backup camera voltage supply module is the digital signal "Reverse gear engaged". The intelligent servo module for DIRECT SELECT transmits the position of the DIRECT SELECT gear selector switch to the central gateway control unit via CAN C.
The central gateway control unit transmits the request to switch on the left backup lamp (E3e3) and right backup lamp (E4e3) to the rear SAM control unit (N10/8), which switches on the backup lamps discretely.
On model designation 164, the activated left backup lamp supplies the electrical pulse to activate the backup camera voltage supply module component over a discrete line (on model designation 251 the right backup lamp performs this function). The backup lamp is then supplied with voltage.
Priority management of COMAND operating, display and control unit
A priority management system integrated in the COMAND operating, display and controller unit ensures that the many functions operate in the correct sequence. Functions of higher priority are carried out before functions of lower priority. A function of lower priority that is currently running (e.g. backup camera system) is automatically deactivated if a function of higher priority (e.g. E-call or Roadside Assistance) is started.
Function restrictions
- Rear-end door open
The backup camera in the rear-end door is positioned so that it functions optimally when the rear-end door is closed. If the rear-end door is open, the driver assist function is not deactivated but the sky (for example) is displayed instead of the entire area to the rear of the vehicle.
- Trailer
A trailer does not affect the driver assist function. The display still appears in the COMAND operating, display and controller unit. Particularly with larger trailers and the associated visibility restrictions, it may be the case that the driver does not have a full view of events in the area to the rear of his/her own vehicle.
Driver termination of backup camera system
- After terminal change (e.g. Tml. 15 ON to tml. 15R ON)
- Gear change out of reverse gear position (selector lever position "R")
- Selection of another system function via soft-key buttons in COMAND operating, display and controller unit.
Termination of backup camera system by COMAND operating, display and controller unit
In case of the following malfunctions, the backup camera system (RFK) is terminated by the COMAND operating, display and controller unit
- Backup camera in rear-end door fails
- Left backup lamp (model designation 164) defective
- Right backup lamp (model designation 251) defective.
| Backup camera (RFK) location of components | Model 164 | GF54.65-P-0005-01GZ |
| Model 251 | GF54.65-P-0005-01RT | |
| Backup camera (RFK), block diagram | Model 164 | GF54.65-P-0005-02GZ |
| Model 251 | GF54.65-P-0005-02RT |