Replace BMW Key Battery If your BMW key isn't able to open your car or turning over the engine, it could be time to change your battery. It's an easy fix. You simply need to remove the key fob, replace the battery and gently place it back. Follow these steps https://www-thekeylab-co-uk01867.blogsidea.com/36364096/this-is-the-good-and-bad-about-bmw-key-fobs