How to Save Money on Audi Battery Replacement Is your Audi key fob not locking and unlocking it? This could be a sign that the battery needs to be replaced. To replace the battery, open the key made of metal and use a flathead screwdriver to open the back cover. https://g2874607.suomiblog.com/how-audi-a4-spare-key-has-changed-my-life-the-better-45475314