Replace BMW Key Battery It's probably the time to change your battery if your BMW key won't allow you to open your car or turn off the engine. It's a simple fix. Simply remove the key fob, then replace the battery and gently place it back. Follow these steps and https://the-keylab59433.thenerdsblog.com/35782141/15-strange-hobbies-that-will-make-you-more-effective-at-bmw-3-series-key-fob