My brother has an 08 320d e90 and recently he says the service logo comes up every now and again (and the clock settings get reset each day) which probably means battery is gone or maybe something else?
He called BMW to ask how much to replace it and they said 350-500, so after he stopped laughing he asked me if I know someone who can get it done. Replacing the battery no problem for me but I do remember these things need to be coded or error pop up etc.
Anyone here that can do it? Don't suppose it works with one of those obd bluetooth things and an app on your phone?