I have a 2001 C240 with the model CM1010 radio/audio system. The battery has been disconnected for some work, and after reconnecting the battery, I don't get the "code" prompt when I turned the radio on. Instead the display lights up and the push buttons function. By that I mean that I mean that I can select the radio, tape, CD, or phone, and the tuner changes stations, but I get no sound. Any suggestions? Thanks.