ghibliss

Can someone please confirm if the backup lithium battery in my 2004 A8L is used exclusively for the On-Star system which was installed in that model year vehicle. I assume that the battery is not used in subsequent model year A8's as they had BlueTooth support and ditched the OnStar system.

The battery is part number 8E0035747 which has a list price of $206.00 at Audi dealers however it is no longer available from the dealers. I doubt the battery is needed since I do not use OnStar however if one did need to replace it you would be better off simply getting the Lithium cells and replacing them in the factory battery housing. The battery is a 16.5 volt Lithium cell which likely means there are four 4.2 volt cells tied together inside of the case.

richard-tx

Only for Onstar. Take out the Onstar and the battery is not needed.