Replace BMW Key Battery It's probably the time to change your battery if your BMW key won't open your car or turn on the engine. Fortunately, it's a simple fix. It's as easy as removing the key fob, then replace the battery and gently put it back. Follow these steps https://the-key-lab18569.goabroadblog.com/29475801/bmw-key-fobs-the-good-and-bad-about-bmw-key-fobs