A while ago I had my knock sensor replaced and I assume to clear the codes they disconnected the battery? Anyway was under the hood looking to see if I could locate the sensor for future reference and noticed a loose red wire with a spade connnector on it hanging free in the vicinity of the positive battery post. There was an identical wire beside it connected to the battery post. Both lead are about 6" long and lead back to what looks like a couple of fuses. Anyway I connected the loose wire to the post beside the other one. Now when the car is started (with the audio unit on) or it is switched on it works briefely then displays "CALL" and ceases working, but remains powered up. I then push the "Band" or "CD" button depending on what I was listening to and all is good again until I switch off the engine. I am assuming its because I reconnected the wire but cant see why. I never noticed it loose before and have never had any audio unit problems before. Coincidence or cause?

2001 Legacy 2.5.

It seems like the power disconnection may have triggered your radio's anti-theft feature. The "CALL" display is probably alerting you to phone your dealer/installer, who can usually tell you how to enter a code that will allow the radio to function as before.