Toyota Mirai key fob battery
5 of the 11 model years listed for the Toyota Mirai 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.
- 2016-2020Smart key
Not confirmed yet
- 2021-2022Smart key
CR2032
FCC ID HYQ14FLATwo sites agree: americankeysupply.com and uhs-hardware.com (checked Nov 1, 2026)
Find CR2032 on Amazon - 2023Smart key (electronic key)
CR2032
FCC ID HYQ14FBAOwner's manual: manua.ls (checked Nov 1, 2026)
Manual text: “Use a CR2032 lithium battery”
Find CR2032 on Amazon - 2024Smart key
Not confirmed yet
- 2024Smart key
Not confirmed yet
- 2025Smart key (electronic key)
CR2450
Owner's manual: manua.ls (checked Nov 1, 2026)
Manual text: “Use a CR2450 lithium battery”
Find CR2450 on Amazon - 2026Smart key (electronic key)
CR2450
Owner's manual: manua.ls (checked Nov 1, 2026)
Manual text: “Use a CR2450 lithium battery”
Find CR2450 on Amazon
Changing the battery
Smart key (push-button start)
- Find the small release on the edge or back of the fob and hold it while you pull out the metal emergency key.
- 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.
- 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.
- Snap the halves back together, slide the metal key home, and press each button, then try the start button from the driver's seat.
On most Toyota smart keys the metal key slides out after you press a small release, and the case opens at the slot it leaves behind.
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.
A CR2450 is 24.5 mm across and 5.0 mm thick, much fatter than a CR2032. A thinner cell will rattle and lose contact, so buy the exact size.
Keep spare coin cells away from small children. A swallowed coin cell can burn the throat within hours; if it happens, go to an emergency room at once.