Hi Roger,
Sorry to hear that you're having issue with your E90. Hopefully the tech article that I attached below will give you some insight and help into troubleshooting your exact issue. If you have any further questions, post a Comment below one of the articles and someone will get back to you with more info. I hope this is useful and best of luck!
BMW 3-Series E90 (2006-2013) Technical Articles - Pelican Parts
-Dmitry