Audi S4 key fob battery
6 of the 26 model years listed for the Audi S4 have a proven battery. The most common answer is CR2032. Rows below run oldest to newest; a year can appear twice when the car came with more than one kind of key.
- 2000-2005Unknown
Not confirmed yet
- 2006-2009Key-head remote
Not confirmed yet
- 2010-2015Smart key
CR2032
FCC ID IYZFBSB802Two sites agree: uhs-hardware.com and bestkeysupply.com (checked Nov 1, 2026)
Find CR2032 on Amazon - 2016Unknown
Not confirmed yet
- 2017-2019Smart key
Not confirmed yet
- 2020Smart key
Not confirmed yet
- 2021-2025Smart key
Not confirmed yet
Changing the battery
Smart key (push-button start)
- Most push-button fobs hide a metal backup key. Press or slide its catch and draw the key out first.
- Look inside the empty key slot for a notch. Put the tip of the metal key or a small flat screwdriver wrapped in tape there and twist gently until the shell splits.
- Pop the old battery out with a toothpick or plastic pick, not a metal blade, and seat the new one with the + side matching the old one.
- Reassemble, refit the emergency key, and check that the car sees the fob when you press start.
A CR2032 is 20 mm across and 3.2 mm thick. CR2032, CR2025 and CR2016 share the same width but not the same thickness, so a swap between them can leave a loose contact or a case that will not close.
Coin cells are a choking and burn hazard for children. Store the spares in their original pack, out of reach.