Replace BMW Key Battery It's probably time to change your battery in the event that your BMW key won't allow you to open your car or turn the engine. It's a simple fix. Simply remove the key fob, then replace the battery and gently place it back. Follow these steps https://thekeylab-co-uk76905.develop-blog.com/36556296/this-is-the-complete-guide-to-bmw-key-fobs