The concept
The parking brake is primarily intended to prevent the vehicle from rolling while parked; it brakes the rear wheels.

See also:
Malfunction
Comfort Access may not function properly if it
experiences interference from local radio waves,
e.g., mobile phones.
If this occurs, open or close the vehicle using the
buttons on the remote co ...
Radar sensors
The radar sensors are located under the rear
bumper.
The system may not be fully functional in the
following situations:
Dirty or icy bumper.
Stickers on the bumper.
A Check Control me ...
Functional readiness of the airbagsystem
When the ignition is switch on,
the warning
lamp in the instrument cluster lights
up briefly and thereby indicates the operational
readiness of the entire airbag system
and the belt tensioner.
...
