Audi S5 key fob battery
8 of the 19 model years listed for the Audi S5 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.
- 2008-2015Smart key
CR2032
FCC ID IYZFBSB802Two sites agree: uhs-hardware.com and bestkeysupply.com (checked Nov 1, 2026)
Find CR2032 on Amazon - 2016-2017Smart key
Not confirmed yet
- 2018-2026Unknown
Not confirmed yet
Changing the battery
Smart key (push-button start)
- Start by freeing the hidden metal key: there is a latch or slide on the case, and the blade comes out once it moves.
- The gap left by the metal key usually has a pry point. A slow twist with a thin flat tool (tape on the tip saves the plastic) opens the two halves.
- Note which side of the old coin cell faces up (usually the side with the writing), lift it out with a plastic tool, and press the new one in the same way.
- Snap the halves back together, slide the metal key home, and press each button, then try the start button from the driver's seat.
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.
If a child might have swallowed a coin cell, treat it as an emergency and get to a hospital right away.