Replace BMW Key Battery If your BMW key isn't opening the doors of your vehicle or turning the engine, it may be time to change your battery. Fortunately, it's a simple fix. You simply need to remove the key fob, then replace the battery, and then gently put it back. https://carkeyreprogramming12879.oblogation.com/29667208/how-to-create-an-awesome-instagram-video-about-bmw-3-series-key-fob