I had a aftermarket battery hooked up to my e60 and constantly got false error messages and it always sounded liked my CD player was running once I turned the car off ..... once i got new OEM battery with correct voltage and had it programmed by my local INDY shop all my problems went away. I guess everyone's experience is different but I would just suck it up and pay the money to have it programmed..... we have to pay to play!!!!!