See also:

The concept
The concept Two radar sensors below the rear bumper monitor the area behind and next to the vehicle at speeds above approx. 30 mph/50 km/h. The system indicates whether there are vehicles ...

Following part replacement
The same breaking in procedures should be observed if any of the components mentioned above have to be renewed in the course of the vehicle's operating life. ...

Remove attached parts following use
Remove auxiliary mirrors, roof or rear luggage racks which are no longer required following use. Attached parts on the vehicle impair the aerodynamics and increase the fuel consumption. ...