See also:

Deactivating HDC
Press the button again and the LED goes out. HDC is automatically deactivated above approx. 37 mph/60 km/h. ...

The concept
In addition to the PDC Park Distance Control, the backup camera, can be switched on. PDC supports you when parking. Objects that you are approaching slowly in front of or behind your vehicle ...

Brake pedal feel
When the system brakes and you also depress the brake pedal, a somewhat different braking feel results. ...