How to Save Money on Audi Battery Replacement Does your Audi key fob experience difficulty locking and unlocking? This could be a sign that the battery is in need of replacement. To replace the battery, open the metal key with flathead, then pop the back cover up with the screwdriver. https://g28-car-key-solutions22786.bloggosite.com/36375227/what-s-the-reason-audi-a4-spare-key-is-everywhere-this-year