How to Save Money on Audi Battery Replacement Is your Audi key fob not locking and unlocking? This may be a sign that the battery needs to be replaced. To replace the battery, open the metal key with an flathead and then open the back cover open using a screwdriver. https://car-locksmiths55654.win-blog.com/9930256/a-help-guide-to-audi-a4-spare-key-from-beginning-to-end