Replace BMW Key Battery It could be the time to change your battery if your BMW key isn't able to open your car or turn off the engine. Fortunately, it's a simple fix. It's as easy as removing the key fob, then replace the battery and gently place it back. https://carkeyreplacements30092.buyoutblog.com/30211560/3-reasons-3-reasons-why-your-bmw-3-series-key-fob-is-broken-and-how-to-fix-it