See also:

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

Priority options
The driver has priority The source selected via iDrive in the front is output on the vehicle loudspeakers and can be selected but not operated from the rear. Other audio or video sources ...

General malfunctions
▷ CD/DVD changers and players have been optimized for performance in vehicles. In some instances they may be more sensitive to faulty CDs/DVDs than stationary devices would be. ▷ ...