How to Save Money on Audi Battery Replacement Is your Audi key fob not locking and unlocking it? This could be a sign the battery is in need of replacement. To replace the battery, simply open the metal key using a flathead and pop the cover off using a screwdriver. https://car-locksmiths06369.full-design.com/what-is-audi-a4-spare-key-to-use-it-72477064