Hello, I need to get help! I bought APS 4 and computer as well.Calculator is not connected at the moment.Today I bought CD changer MC 3196.I have everything correctly connected(cable is NEW) but changer is not detected by APS 4 radio.Changer works correctly.Question is, do I need to save or not at Mercedes via diagnostic radio and changer? What I have noticed is, I can’t activate changer from radio with key CC-CD.Comes only display No CC. I don’t know if it’s wrong with radio or changer. Thanks Gruss Zvonimir