Replace BMW Key Battery If your BMW key isn't able to open your vehicle or turning the engine, it might be time to change your battery. It's simple to fix. All you need to do is remove the cover for the key fob take it off, then replace the battery, https://car-key-replacement97658.activablog.com/29613970/tips-for-explaining-bmw-3-series-key-fob-to-your-boss