Hyundai Ioniq key fob battery
2 of the 6 model years listed for the Hyundai Ioniq 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.
- 2017Smart key
Not confirmed yet
- 2018-2019Smart key
Not confirmed yet
- 2020-2021Smart key
CR2032
FCC ID TQ8-FOB-4F11Two sites agree: uhs-hardware.com and bestkeysupply.com (checked Nov 1, 2026)
Find CR2032 on Amazon - 2022Smart key
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.
- Use the slot where the metal key sat. Twist, do not lever hard, and work along the seam until the halves separate.
- 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.
- Reassemble, refit the emergency key, and check that the car sees the fob when you press start.
Hyundai smart keys usually have a button that releases the mechanical key; a flat tool in the gap then opens the case.
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.