Hi. I have a '98 A6 2.8 Quattro. It has the Audi Concert stereo in it but the volume **** is unresponsive (but does work to turn the system on and off). The guy i bought it off said that it was locked and needed a code, but the display does not say "safe". Does this guy know what he is talking about or was he just blowing smoke and there is a bigger issue with the head unit? Thank you for any input.

 

Probably too late, but you more than likely have a bad volume control - mine did the same thing, except it would actually GAIN volume when turning down, yikes. Replaced with a $75 JVC KD-X50BT single DIN unit, sounds 10X better than the factory unit plus I now have Bluetooth, Pandora and iPhone control, etc. just no CD.