How to Save Money on Audi Battery Replacement Is your Audi key fob having trouble locking and unlocking it? This may be a sign that the battery must be replaced. To replace the battery, open the key made of metal and use a flathead screwdriver to remove the back cover. https://car-locksmiths13564.bloggazza.com/29166437/what-is-audi-a4-spare-key-and-why-is-everyone-speakin-about-it