Replace BMW Key Battery If your BMW key isn't opening your car or turning over the engine, it could be time to change your battery. Fortunately, it's an easy fix. You simply need to remove the key fob, replace the battery, and then gently put it back. Follow these steps https://the-key-lab73275.blogoscience.com/36322884/bmw-key-fobs-tips-from-the-top-in-the-industry