These instructions apply to the Hyundai Tucson Mk3 (TL) 2015-2020.
For other models, please choose your vehicle here.
If the remote or smart key on your Hyundai Tucson Mk3 (TL, 2015–2020) only works from up close, or has stopped locking the car, the fob’s coin battery is almost always the cause — and it is a quick change. This guide shows how to swap the key fob battery and what needs a dealer.
First, Rule Out the Battery
A weak fob battery is the number-one reason a Tucson remote becomes unreliable — short range, needing several presses, or no response. Most Tucson keys use a CR2032 coin cell.
Replacing the Fob Battery
The Tucson came with two fob styles — one opens at a cover, one needs the blade out first:
- Type 1: insert a small screwdriver and prise off the button-cell cover, lift out the old CR2032, fit the new cell positive (+) side up, and refit the cover.
- Type 2: press the release button and pull out the mechanical insert key first, then remove the key cover to reach the cell and renew it the same way.
After a battery change the key keeps its programming — no re-pairing needed.
Lost Key or Adding a Spare
The Tucson cannot have a key programmed without a diagnostic tool. A lost or extra smart key must be ordered and coded by a Hyundai dealer or an auto-locksmith — there is no owner sequence. The home job is limited to renewing the battery in a key that already works.
If a Fresh Battery Doesn’t Fix It
- Check the cell type and polarity — a CR2032 fitted the wrong way gives no response.
- Use the mechanical insert key to unlock the door, and hold the smart key against the start button to start if its battery is flat.
- Still nothing from any key? A receiver or body fault may be involved — check the code on autodtcs.com.
Frequently Asked Questions
What battery does the Tucson key take?
Most use a CR2032 coin cell. Check the old one when you open the fob to confirm.
Do I need to reprogram after changing the battery?
No — programming is retained. Just fit the CR2032 the right way round and test.
Can I program a new Tucson key myself?
No — the Tucson needs a diagnostic tool to register a key, so a new or replacement key must be coded by a Hyundai dealer or locksmith.
How do I start the car if the smart key is dead?
Use the mechanical insert key to unlock, then hold the smart key against the start button and press — the car reads the transponder directly.
If the remote stopped working after a battery disconnection, see our Hyundai Tucson battery disconnect/reconnect guide.
Independent guide — not affiliated with Hyundai. Always follow your official service manual and safety precautions. Read our full disclaimer.