Replace BMW Key Battery It's probably time to change your battery if your BMW key won't allow you to open your car or turn the engine. It's a simple fix. You simply need to remove the key fob, then replace the battery and gently put it back. Follow these steps https://car-key-repairs15795.xzblogs.com/71404132/15-reasons-why-you-shouldn-t-ignore-bmw-3-series-key-fob