unble to connect phone via usb to car media player

[AC Question]

Ihave a galaxy note4 and have previously been able to play music via usb connection in my car which is a 2010 mini clubman but since i downloaded last android update i am unable to connect to car sterio via usb i get a message stating 'empty' implying that there is no music files stored on my phone, can anyone advise if there is any software available or android update that i can download so that i can reconnect my phone via usb cable once again. I have aux cable but this is not legal as it relies on using phone when selecting tracks as apposed to using car sterio when its connected via usb hope you can Help......