Reversing Camera (RFK), Function - GF54.65-D-0005TSA

Model 907 

with code FR8 (Rear view camera) 

Block diagram 

Function requirements, general 

• Circuit 15 ON:

  The electronic ignition lock control unit (EZS) sends the status of circuit 15 over the user interface CAN (CAN HMI) to the reversing camera (RFK) control unit.

• Function enabled through control menu on the head unit:

  The head unit sends the function enable over the user interface CAN to the reversing camera (RFK) control unit.

• Drive range "R" (with automatic transmission) engaged

  During commissioning and after being replaced, the reversing camera must be recoded using the diagnostic tester. The reversing camera is calibrated automatically after initial startup.

Reversing camera, general 

The reversing camera is an optical parking aid. Its tasks include the recording of images of the area to the rear of the vehicle, the generation of dynamic and static guide lines and the transmission of the picture data to the head unit. The pictures recorded by the reversing camera are processed accordingly by the integrated reversing camera (RFK) control unit. The current driving path is shown on the Audio/COMAND display control unit in the form of guide lines based on the vehicle dimensions, vehicle speed and steering wheel angle.

The reversing camera function comprises the following subfunctions:

• Activate, deactivate function sequence for reversing camera.
• Function sequence for picture recognition, picture output

Function sequence for activating/deactivating reversing camera 

The reversing camera (RFK) control unit when the reverse gear or drive range "R" is engaged.

With manual transmission:

Engaging of the reverse gear is detected by the backup lamp switch. The powertrain control unit reads in the signal of the reversing lamp switch directly, uses it to generate the "Reverse gear engaged" signal and sends this over the suspension FlexRay to the EZS control unit. Wth automatic transmission:

Drive range "R" is engaged by the fully integrated transmission control electric controller unit (VGS) (model 907). The "Drive range R engaged" status is then sent over the drive CAN, powertrain control unit and the suspension FlexRay to the EZS control unit.

The EZS control unit uses the incoming information to generate the "Reverse gear engaged" status that is independent of the transmission variant and sends this over the user interface CAN to the reversing camera control unit.

The reversing camera (RFK) control unit then activates or deactivates the reversing camera function.

The reversing camera (RFK) control unit is deactivated under the following conditions:

• Vehicle speed during forward travel > 16 km/h
• Drive range "P" engaged (automatic transmission)
• Circuit 15 OFF

The direction of travel is defined using the wheel rotation direction.

The vehicle speed is calculated from the wheel speed.

The ESP® control unit sends the corresponding information over the suspension FlexRay, EZS control unit and the user interface CAN to the instrument cluster. The instrument cluster calculates the vehicle speed to be displayed and sends it over the user interface CAN to the reversing camera (RFK) control unit.

Function sequence for picture recognition, picture output 

The reversing camera (RFK) control unit sends the request to display the image data over the user interface CAN to the head unit. The reversing camera (RFK) control unit also sends the recorded image data and sends it over the HSVL to head unit. The head unit activates the Audio/COMAND display control unit over the telematics CAN and sends the image data over the HSVL to the Audio/COMAND display control unit. The image data are then shown in the Audio/COMAND display control unit.

The reversing camera (RFK) control unit uses the steering wheel angle and stored vehicle parameters (lane and exterior contour of the vehicle) to calculate guide lines that are then shown on the display. The steering wheel angle is recorded by the steering wheel angle sensor, which is integrated in the steering column tube module (MRM) control unit. The steering column tube module (MRM) control unit sends information on the steering wheel angle over the suspension FlexRay, EZS control unit and the user interface CAN to the reversing camera (RFK) control unit.

The reversing camera function can be operated in the following modes:

• Maneuvering mode
• Wde-angle mode
• Trailer mode (with code E40 (Trailer socket, 7-pin) or with code E43 (Trailer socket 13-pin))

The selection is made using the head unit operating menu.

If the reversing camera was previously operated in maneuvering mode, the maneuvering mode is activated again when reverse gear or the "R" gear range is engaged.

Maneuvering mode: 

The maneuvering mode assists the driver when reversing while parking. To do so, dynamic guide lines are shown in the display in addition to the pictures recorded by the reversing camera.

Display of dynamic and static guide lines 

When the reverse gear or drive range "R" is engaged, yellow guide lines are shown. They indicate the path which the vehicle would follow with the current steering wheel angle. The yellow guide lines are automatically adapted as the steering wheel angle changes.

Trailer mode: 

Trailer mode (with code E40 (Trailer socket, 7-pin) or with code E43 (Trailer socket 13-pin)) supports the driver when reversing towards a trailer by zooming into the ball head of the trailer hitch. To do so, special guide lines are shown in the display in addition to the pictures recorded by the reversing camera.

View of the area to the rear of the vehicle in wide-angle mode 

Display of distance lines in the trailer mode 

As soon as the driver engages reverse gear or drive range "R", the virtual steering angle (3) and the distance lines around the ball head (f) are shown. The virtual steering angle (3) indicates the route to the driver which the vehicle would follow with the current steering wheel angle. This curve is automatically adapted to the situation as the steering angle changes. The length of the guide line corresponds to approx. 1 m.

The distance line around the ball head (f) is shown with a radius of 0.3 m around the ball head.

The guide lines are all hidden during an attempted correction (forward travel) and shown again once the reverse gear or drive range "R" is engaged.

Wide-angle mode: 

The wide-angle mode provides assistance when reversing into traffic areas that are not clearly visible. The reversing area is shown in the Audio/COMAND display control unit as a three-part view with an angle of 180°. This provides a clear view into a traversing road in good time, e.g. when reversing out of a narrow lane.

Electrical function schematic, reversing camera	Model 907	PE54.65-D-2051-97TSA
Overview of system components, parking system		GF54.65-D-9992TSA