Replace BMW Key Battery It might be the time to change your battery if your BMW key isn't able to open your car or turn on the engine. Fortunately, it's a simple fix. You simply need to remove the key fob, replace the battery and gently put it back. Follow https://car-key-replacement48480.blogdun.com/30732154/15-amazing-facts-about-bmw-3-series-key-fob