How to Save Money on Audi Battery Replacement Does your Audi key fob have issues locking and unlocking? This could indicate that the battery needs to be replaced. To replace the battery, you must open the metal key using a flathead and pop the back cover up with the screwdriver. https://g28-car-key-solutions22786.bloggosite.com/36395553/a-how-to-guide-for-audi-a4-spare-key-from-beginning-to-end