See also:

Visual warning
The approach of the vehicle to an object can be shown on the Control Display. When the distance to an object is small, a red bar is shown in front of the vehicle, as it is in the PDC display. ...

Switching on/off manually
Press the button. On: the LED lights up. Off: the LED goes out. If Top View is displayed, switch on the backup camera via the iDrive. ...

Activating HDC
Press the button; the LED above the button lights up. ...