Replace BMW Key Battery If your BMW key isn't opening your car or turning on the engine, it may be the time to replace your battery. It's an easy fix. It's as easy as removing the key fob, replace the battery, and then gently put it back. Follow these steps https://thekeylab-co-uk62880.bloggip.com/30150880/why-all-the-fuss-over-bmw-key-fobs