Reversing Camera (RFK), Function - GF54.65-P-0005CEJ

MODEL 204.0/2 with CODE (218) Backup camera with CODE (498) Japan version as of Model Year 2009/AEJ 08

MODEL 204.3 with CODE (218) Backup camera with CODE (498) Japan version

MODEL 204.9 up to 31.5.12 with CODE (218) Backup camera with CODE (498) Japan version

Fig 1: Reversing Camera - Block Diagram

Function requirements, general

Circuit 15 ON
Trunk lid (model 204.0/3) or liftgate (model 204.2/9) closed
Reversing camera function activated through the COMAND controller unit
Reverse gear (transmission 711, 716) or gear range "R" (transmission 722) engaged

The electronic ignition lock control unit sends the status of circuit 15 via the interior CAN to the reversing camera control unit.

The trunk lid rotary tumbler switch (model 204.0/3) in the liftgate central locking motor (model 204.0/3) records the status of the trunk lid (open or closed).

The liftgate rotary tumbler switch (model 204.2/9) in the liftgate central locking motor (model 204.2/9) records the status of the liftgate (open or closed).

The rear SAM control unit reads in the status of the trunk lid rotary tumbler switch or the liftgate rotary tumbler switch directly and then sends it over the body CAN to the reversing camera control unit.

If the trunk lid or liftgate is not closed, the picture on the Audio/COMAND display is overlaid with a warning message.

During initial startup, when working on the reversing camera or when working on the trunk lid or the liftgate, the reversing camera has to be calibrated again using the diagnosis tester.

Reversing camera, general

The reversing camera function enables the driver to select between the following parking modes:

Cross parking (reverse parking)
Longitudinal parking (parallel parking)

The corresponding selection takes place at the operating level of the COMAND controller unit. The last selected mode of parking is activated by engaging gear range "R".

In addition, voice assistance can be activated when parallel parking.

The operating instructions for this are described in a separate document.

The reversing camera function comprises the following subfunctions:

Reversing camera function sequence
Front passenger outside mirror camera activation function sequence (on model 204.9)

Reversing camera function sequence

When reverse gear or gear range "R" is engaged, the reversing camera function is activated.

The "reverse gear engaged" status is defined as follows.

Vehicle with transmission 711, 716:

Engagement of reverse gear is defined via the status of the backup lamp switch, which is read in directly by the front SAM control unit.

Vehicle with transmission 722:

The request to engage gear range "R" is defined by the corresponding selector lever position.

The electronic selector lever module control unit sends the selector lever position over the drive train CAN, ME-SFI [ME] control unit and the chassis CAN to the front SAM control unit.

Located in the front SAM control unit are two microprocessors, one for control of basic functions e.g. the exterior lights, and the second for control of the central gateway functions. Both processors communicate with each other internally via interior CAN.

Using all incoming information, the microprocessor which controls the central gateway functions generates the "reverse gear engaged" signal (irrespective of the transmission variant) and sends this signal to the reversing camera control unit over the interior CAN.

The reversing camera control unit then supplies power to the reversing camera.

The pictures recorded by the reversing camera are read in and processed as CVBS signals by the reversing camera control unit. The reversing camera control unit makes calculations based on the steering angle and the stored vehicle guideline parameters, which are shown on the pictures taken.

The steering angle is recorded by the steering angle sensor. The steering column tube module control unit reads in the signals from the steering angle sensor and sends them to the reversing camera control unit over the chassis CAN, front SAM control unit and interior CAN.

The reversing camera control unit sends the processed pictures as Color Video Baseband Signals to the COMAND controller unit, which then activates the Audio/COMAND display over the telematics CAN. For vehicles without code (255) AMG Performance Media, the COMAND controller unit sends the picture signals over the low voltage differential signaling (LVDS) line to the Audio/COMAND display.

For vehicles with code (255) AMG Performance Media, the COMAND controller unit sends the picture signals over the low voltage differential signaling (LVDS) line to the AMG Performance Media control unit.

The AMG Performance Media control unit over another low voltage differential signaling (LVDS) line to the Audio/COMAND display. The Audio/COMAND display then shows the pictures recorded by the reversing camera.

Additional function requirements for front passenger outside mirror camera activation (on model 204.9)

Front passenger mirror not folded in
Passenger door CLOSED
Vehicle speed v < 15 km/h

Front passenger outside mirror camera activation function sequence (on model 204.9)

Pressing the corresponding softkeys on the COMAND controller unit activates the front passenger outside mirror camera.

The COMAND controller unit then sends the request over the interior CAN to the reversing camera control unit.

The reversing camera control unit activates the front passenger outside mirror camera. The steering angle and stored vehicle parameters are used by the reversing camera control unit to calculate guide lines which are then integrated into the received camera pictures.

The reversing camera control unit then sends the processed pictures as Color Video Baseband Signals to the COMAND controller unit, which then activates the Audio/COMAND display over the telematics CAN.

For vehicles without code (255) AMG Performance Media, the COMAND controller unit sends the picture signals over the low voltage differential signaling (LVDS) line to the Audio/COMAND display.

The AMG Performance Media control unit over another low voltage differential signaling (LVDS) line to the Audio/COMAND display.

The Audio/COMAND display then shows the pictures recorded by the front passenger outside mirror camera.

	Electrical function schematic, reversing camera		PE54.65-P-2051-97FAA
	Reversing camera (RFK), operating notes		GF54.65-P-0005-03CEJ
	Overview of system components of parking assistance systems		GF54.00-P-9997CE