Replace BMW Key Battery It might be time to change your battery in the event that your BMW key won't open your car or turn the engine. Fortunately, it's a simple fix. It's as easy as removing the key fob, then replace the battery, and then gently put it back. https://thekeylab18489.tokka-blog.com/30391343/speak-yes-to-these-5-bmw-key-fobs-tips