Replace BMW Key Battery If your BMW key isn't opening the doors of your car or turning on 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 gently put it back. https://the-key-lab11455.activoblog.com/31109238/why-bmw-key-fobs-may-be-greater-dangerous-than-you-think