Replace BMW Key Battery If your BMW key isn't able to open your car or turning on the engine, it could be time to change your battery. Fortunately, it's a simple fix. Simply remove the key fob, then replace the battery and gently put it back. Follow these steps and https://car-key-repairs07930.bcbloggers.com/29633714/20-resources-that-will-make-you-better-at-bmw-3-series-key-fob