I don't know if this is your problem but about 4 months ago i unhooked my battery and when i hooked it back up i got the samething. It's an anti-theft so if someone steals it they can't use it without a code. I had to take out the stock deck and look at the model number on the back and call my acura dealer and then they gave me a code. If thats not it then i don't know.