Replace BMW Key Battery If your BMW key isn't opening the doors of your car or turning on the engine, it could be the time to replace your battery. It's a simple fix. It's as easy as removing the key fob, then replace the battery and gently put it back. https://car-key-repairs43103.blogpayz.com/30174454/how-to-recognize-the-bmw-key-fobs-that-s-right-for-you