OK so i decided to try out this so called wonderful German Engineering and I am already losing confidence in their work. So i just bought a 2004 Audi A4 - Auto - 51K (Private Sale) and when I checked it out it was great...no problems.

When i was driving home that night i put on some music and the Bose system was nice, I had a tape adapter in which was hooked up to my iPod, I took out the tape and was getting ready to put in a CD. After i touched the CD button i received Error 3. Apparently the previous owner forgot his CDs in there. After this occurred the radio turned on but would never play again, all I heard was this loud humming sound kinda whining when you push and release the gas.

So i pulled over and turned the car off. When you put the key in without turning it, it's a real loud hum kinda sounds like something from a space ship. Had to drive back 4 hours with no music, sucks!!!

So that night when I got home i parked and went out later and the car would not start. I tested the battery and it was about 12.57 Volts which means it's about 80% charged. The car was able to start with a Jump though. I drove it around the block and maybe 20 minutes later it wouldn't start again.

What the heck is going on with this car!! This is insane... Any help would be greatly appreciated.

 

Sounds like you have a power draw. Probably your radio. Try unplugging it all together and see if that changes any thing.
Btw, I have a 2002 A4, and there is a very odd sound that I have never been able to explain, and it comes from the glove box. I'm assuming it has to do with my heater. I don't know, just throwing that out there in case it sounds familiar.

If all else fails, take it to a mechanic. See what they say.

 

is the humming coming from the radio. I know there is some sort of fan or something in the climate control that could create this sound. Someone correct me for the proper location of that noise and soultion. .

 

Didn't you post the same question on AZ? Anyways, Error 3 is cd's jammed in the cassete inside your changer. You can disconnect the battery and reconnect it, that might reset your radio causing it to "spit" all the cd's out and reset your voltage surge causing your humming noise... Good luck.