Replace BMW Key Battery If your BMW key isn't opening the doors of your car or turning over the engine, it may be time to change your battery. It's simple to fix. It's as easy as removing the key fob, then replace the battery, and then gently put it back. https://carkeyprogramming96525.eedblog.com/30290777/10-bmw-key-fobs-related-projects-that-stretch-your-creativity