Replace BMW Key Battery If your BMW key isn't able to open your car or turning over the engine, it might be the time to replace your battery. It's an easy fix. Simply remove the key fob, then replace the battery, and then gently put it back. Follow these steps https://the-keylab28449.ageeksblog.com/29438261/10-myths-your-boss-has-concerning-bmw-3-series-key-fob