Replace BMW Key Battery It's probably time to change your battery If your BMW key isn't able to open your car or turn off the engine. It's a simple fix. All you need to do is take off the cover of the key fob, carefully remove and replace the battery, https://thekeylab95140.kylieblog.com/30601392/three-reasons-why-3-reasons-why-your-bmw-3-series-key-fob-is-broken-and-how-to-fix-it