Replace BMW Key Battery It's probably the time to change your battery if your BMW key won't allow you to open your car or turn on the engine. It's simple to fix. All you have to do is remove the key fob cover then carefully remove and replace the battery, https://the-key-lab73275.blogoscience.com/36269291/7-helpful-tips-to-make-the-most-out-of-your-bmw-key-fobs