Changing the Battery in Your mini key fob cover uk Key Fob The key fob is a handy way to lock and unlock your car key cutting and Programming cost from an extended distance. It also allows you to activate the panic button on your vehicle that can deter burglaries. If your device ceases to function, it can be fixed with some simple steps. First, make sure that the battery is fresh. Then, try taking it from the ignition by pressing the button to lock three times quickly. Battery Switching the battery on your key fob is one of the most straightforward fixes. The key fob is powered by a tiny coin-shaped 3V battery (CR2032 or CR2025) that is usually available in general stores, home improvement shops, and a few auto parts stores. Make sure to use a new battery -older batteries are typically no longer good for anything and could damage the circuit board. Begin by opening the fob. You may need to make use of a flat screwdriver to divide the two halves.