I have a 2008 BMW 3 Series estate. It was fine when I bought it 5 months ago, apart from a problem with the rear tailgate window which wouldn't open and this was fixed. A few weeks ago I noticed when I unlocked it the window on the tailgate popped open and wouldn't close. When I started then engine a fault warning light appeared and the clock and date needed to be reset. My local mechanic has plugged in his computer and noted quite a lot of fault codes which he doesn't recognise. The issues with the clock and rear window appear intermittently. I have tried disconnecting the negative on the battery to reset but problem remains.