How to Upgrade Your BMW Key 1 Series If your BMW key fob isn't functioning correctly, it most likely needs an upgrade to the battery. They are also referred to as coin batteries and can be replaced with just a few steps. Each key is connected to a driver profile https://g28-car-keys26962.verybigblog.com/30197255/5-bmw-battery-replacement-key-instructions-from-the-pros