How to Save Money on Audi Battery Replacement Is your Audi key fob having difficulty locking and unlocking it? This could be a sign the battery is in need of replacing. To replace the battery, open the metal key using flathead, then pop the back cover up using a screwdriver. https://g28carkeys35648.qodsblog.com/29893189/10-great-books-on-audi-a4-spare-key