Cd player display says no CD changer on vw passat 2002 what should you do?

Short Answer: Check the connections between the stereo (head unit) and the CD player. Perhaps one of the plugs has become disconnected. Long Answer: I recently bought a used 2001 Volkswagen Passat GLX 4Motion Wagon. There were clear indications the battery had been disconnected. For example, the clock was off by about four hours, and the original owner lived in the same time zone! Also, the stereo was displaying the "SAFE" message, which I later learned was related to having the battery disconnected. Finally, reviewing photos of the engine compartment (provided before the sale) the battery pictured did NOT match the battery I removed from the vehicle!! After replacing the battery, I needed a 4-digit security code to unlock the unit's anti-theft feature. The card with the code on it had been removed from the manual by the previous owner. So, I had to remove the unit to access the serial number. This number (along with the VIN) was provided to a local dealer, and they eventually responded with the appropriate code. The head unit then functioned correctly. Some weeks later I tried to play a CD, but the player was not responding. When I pressed the "CD" button on the stereo, it displayed the "NO CHANGER" message. This was rather perplexing. I eventually removed the stereo (again) and found some connectors which weren't attached to the stereo, and there seemed to be a place on the stereo to plug in these connectors. However, the wires seemed far too short to reach the head unit. So, I removed the CD player SIMULTANEOUSLY, and this allowed the wires some additional "free play". Before reinstalling (pushing the units back into the dash), I turned on the stereo and depressed the "CD" button again. This time I got a message which said "NO DISC". So, I was satisfied the problem was likely resolved. A subsequent test of the unit proved it worked, but only with "store bought" CDs, not those made on a PC (in my case... CDs burned with Nero Burning ROM). Everything is working fine now. I'm now thinking of getting the 5 CD changer, which installs in a compartment in the cargo area. VW has the vehicle pre-wired to accept a changer. But I need to research the matter more, as some sites recommend professional installation. There may be some quirks or tricks associated with these units, and I want to make sure the unit can be installed easily before I fork over the bucks for it! I hoped this helped.