(Back Up/Reversing Camera (RFK), Function - GF54.65-P-0005GR)
MODEL 166
up to model year 2016
with CODE 218 (Rear view camera)
Except CODE 498 (Japan version)
With CODE 498 (Japan version)
Function requirements, general
- Terminal 15 ON
- Liftgate closed
- Function of reversing camera enabled through the control menu of the COMAND® controller unit
The electronic ignition lock control unit transmits the circuit status of circuit 15 over chassis CAN 2 to the reversing camera.
The rear SAM control unit transmits the status of the liftgate (liftgate open or closed) via interior CAN, electronic ignition lock control unit and chassis CAN 2 to the reversing camera.
If the liftgate is not closed, the picture shown on the Audio/COMAND® display is overlaid with a warning message and the guide lines are hidden.
During initial startup, when working on the reversing camera or when working on the liftgate, the reversing camera has to be calibrated again using the diagnosis tester.
Reversing camera, general
The reversing camera is an optical parking and maneuvering aid. Its tasks include capturing pictures of the area to the rear of the vehicle, generating dynamic guide lines and sending picture signals to the COMAND® controller unit. The pictures recorded by the reversing camera are processed accordingly by the integrated control unit. The current driving path is then shown in the Audio/COMAND® display based on the vehicle dimensions, vehicle speed and the steering angle.
The reversing camera function comprises the following subfunctions:
- Function sequence for activating/deactivating reversing camera
- Function sequence for actuating rear camera cover (as of 01.07.2013)
- Function sequence for picture recognition, picture output by reversing camera
Function sequence for activating/deactivating reversing camera
The reversing camera is automatically activated by engaging gear range "R". The reversing camera is deactivated as soon as any gear range other than "R" is engaged. Automatic activation/deactivation of the reversing camera must be enabled via the corresponding operating level of the COMAND® controller unit.
To do so, the COMAND® controller unit sends the status of the function via interior CAN, electronic ignition lock control unit and chassis CAN 2 to the reversing camera.
Gear range "R" is engaged through the fully integrated transmission control unit. The fully integrated transmission control unit then sends the status "gear range R engaged" to the electronic ignition lock control unit via the drive train CAN, CDI control unit or ME-SFI [ME] control unit and chassis CAN 1. The electronic ignition lock control unit uses this to generate the "Reverse gear engaged" status and sends this over the chassis CAN 2 to the reversing camera.
The reversing camera function is now activated.
On vehicles with CODE 498 (Japan version), pressing the corresponding softkeys on the COMAND® controller unit activates the front passenger outside mirror reversing camera. The COMAND® controller unit sends the request "reversing camera mode" to the reversing camera via interior CAN, electronic ignition lock control unit and chassis CAN 2.
The front passenger outside mirror reversing camera can only be activated when the following conditions are fulfilled:
- Front passenger mirror not folded in
- Passenger door CLOSED
- Vehicle speed v < 15 km/h
The right front door control unit transmits the position of the mirror housing on the passenger side and the status of the front passenger door to the reversing camera via interior CAN, electronic ignition lock control unit and chassis CAN 2.
Function sequence for actuating rear camera cover (as of 01.07.2013)
A camera cover is used to protect the camera lens against dust. The camera cover is automatically opened or closed to match the status of the reversing camera (activated or deactivated).
The camera cover is opened and closed when requested by the reversing camera. The reversing camera sends this via chassis CAN 2, electronic ignition lock control unit and interior CAN to the rear control unit. The rear control unit then actuates the rear camera cover motor directly. The status of the camera cover (open or closed) is registered by the switch for the rear camera cover motor. The rear control unit reads in the status of the rear camera cover motor switch and sends this over the interior CAN, electronic ignition lock control unit and the chassis CAN 2 to the reversing camera.
To clean the camera lens, the camera cover can be opened using the control menu of the COMAND® controller unit. During this, no picture is shown in the Audio/COMAND® display. The COMAND® controller unit sends the request "service mode" via interior CAN, electronic ignition lock control unit and chassis CAN 2 to the reversing camera. Further course of signals corresponds to the automatic opening and closing of the camera cover.
Function sequence for picture recognition, picture output by reversing camera
At the same time as the rear camera cover is opened, the reversing camera sends the "Reversing camera ON" status over chassis CAN 2, electronic ignition lock control unit and interior CAN to the COMAND® controller unit.
On vehicles except CODE 498 (Japan version), the reversing camera then sends the recorded pictures as Color Video Baseband Signal (CVBS) to the COMAND® controller unit. The COMAND® controller unit then activates the Audio/COMAND® display over the telematics CAN, processes the picture signals from the reversing camera and sends the corresponding picture data over the low voltage differential signaling (LVDS) line to the Audio/COMAND® display.
On vehicles with CODE 498 (Japan version), the reversing camera sends the recorded pictures as CVBS to the reversing camera electronics first, which then forwards the pictures as CVBS to the COMAND® controller unit.
To optimize the display of the pictures shown, in addition to the optical compensation in the lens, an electronic compensation through the reversing camera is also carried out.
The reversing camera calculates the guide lines that are superimposed onto the pictures shown in the Audio/COMAND® display, taking the rotation angle and stored vehicle parameters (vehicle lane and exterior contour) into account. The steering angle is recorded by the steering wheel angle sensor. The steering column tube module control unit directly reads in the signals of the steering wheel angle sensor and sends these via chassis CAN 1, electronic ignition lock control unit and chassis CAN 2 to the reversing camera.
The reversing camera function enables the driver to select between the following modes:
- Maneuvering mode
- Trailer mode (with CODE 550 (Trailer hitch))
The corresponding selection takes place at the operating level of the COMAND® controller unit.
If the reversing camera was previously operated in maneuvering mode, the maneuvering mode is activated again when the "R" gear range is engaged. This does not apply when the reversing camera was previously operated in trailer mode.
Maneuvering mode:
The maneuvering mode assists the driver when reversing while parking. In doing so, dynamic guide lines are also shown on the Audio/COMAND® display in addition to the pictures recorded by the reversing camera.
Display of dynamic guide lines (with wheels in straight-ahead position)
Display of dynamic guide lines (with wheel turned to the right)
Virtual steering angle (yellow guide lines):
The yellow guide lines are shown as soon as the driver turns the steering wheel. They indicate to the driver the path which the vehicle would follow with the current steering wheel angle. This curve is automatically adapted as the steering wheel angle changes. The distance between the yellow guide lines is slightly more than the vehicle width.
Parking procedure:
In order to park, the driver must now adapt the steering wheel angle until an outer line of the yellow guide lines in the Audio/COMAND® display touches the parking space marking. This parking space marking can, e.g. be another vehicle or a line on the asphalt. The driver must then continue reversing and adapting the steering wheel angle until the displayed parking space limits run parallel to the current direction of travel.
Next the driver must turn the steering wheel back into the straight-ahead position in order to drive in a straight line up to the final park position in the parking space.
Display of distance lines in the maneuvering mode
The distance lines inform the driver of the distances between the virtual bumper and obstacles.
Trailer mode (with code 550 (Trailer hitch)):
Trailer mode supports the driver when reversing to a trailer by zooming into the ball head. When reversing, special guide lines are also shown on the Audio/COMAND® display in addition to the pictures recorded by the reversing camera.
Display of distance lines in the trailer mode
Virtual steering angle (yellow guide line)
As soon as the driver turns the steering wheel, this yellow guide line is displayed. They indicate to the driver the path which the vehicle would follow with the current steering wheel angle. This curve is automatically adapted as the steering wheel angle changes. The yellow guide line is shown at a distance of approx. s = 1 m to the trailer hitch.
Distance line around the ball head (red guide line):
The red distance line is a static display element on the Audio/COMAND® display and notifies the driver about the distance over a radius of 0.25 m around the ball head.
The guide lines are hidden for an attempted correction (forward travel) in the Audio/COMAND® display and shown again when gear range "R" is engaged again taking the following parameters into consideration:
- t < 10 s
- v < 10 km/h
- s < 10 m forward travel
If these parameters are exceeded the picture recorded by the reversing camera is no longer shown on the Audio/COMAND® display.
The reversing camera then remains in standby mode.
The vehicle speed is calculated from the wheel speeds, the direction of travel is defined by the wheel rotation directions. The Electronic Stability Program control unit sends this information over chassis CAN 1, electronic ignition lock control unit and chassis CAN 2 to the instrument cluster and to the reversing camera. The reversing camera uses this information to calculate the vehicle speed and define the direction of travel.
In addition, the instrument cluster uses the wheel speeds to calculate the vehicle speed to be displayed and it sends this over the chassis CAN 2 to the reversing camera.
On vehicles with CODE 498 (Japan version), pressing the corresponding softkeys on the COMAND® controller unit activates the front passenger outside mirror reversing camera. To do so, the COMAND® controller unit sends the request via interior CAN, electronic ignition lock control unit and chassis CAN 2 to the reversing camera.
Then the reversing camera deactivates its video output.
The reversing camera electronics then no longer receive any picture data from the reversing camera and now read in the picture data from the front passenger outside mirror reversing camera as FBAS signal.
The reversing camera electronics subsequently sends the pictures taken from the front passenger outside mirror reversing camera as CVBS signals to the COMAND® controller unit, which then activates die Audio/COMAND® display over the telematics CAN. The COMAND® controller unit transmits the processed picture data from the front passenger outside mirror reversing camera via low voltage differential signal (LVDS) line to the Audio/COMAND® display.
The stored vehicle parameters are then used by the front passenger outside mirror reversing camera to calculate static guide lines which are then integrated into the camera pictures.
Display of front passenger outside mirror reversing camera distance lines (with CODE 498 (Japan version))
The picture shows the important points of the vehicle for orientation purposes.
The orientation line running parallel to the vehicle is a distance line. The reference line running vertically relative to the distance line indicates the front axle.
| Electrical function schematic, reversing camera | MODEL 166 up to model year 2016 with CODE 218 (Rear view camera) with CODE 498 (Japanese version) | PE54.65-P-2051-97NAA | |
| MODEL 166 up to model year 2016 with CODE 218 (Rear view camera) with CODE 498 (Japanese version) | PE54.65-P-2051-97NAB | ||
| Overview of system components of parking assistance systems | GF54.00-P-9997GR |