CDC broken?

[mikkoata]

I bought a CD-changer for my friend's Passat. He has the MFD2 already in the car, also had to buy the cable between. Now when installed, the discs can be seen from the MFD, but they cannot be accessed. Do You think that the CDC is broken, or is there something coding to be done also or is it always plug'n play? Broken/wrong wire perhaps? Where to start troubleshooting..?

Cheers :beerchug: