Owner guide · Michigan City Hyundai · Michigan City, IN
Hyundai Key Fob Battery Replacement
When the low key battery message appears, Hyundai's advice is simple: replace the smart key battery. Here is the battery Hyundai lists, the three-step swap from the owner's manual, what else can stop a key working and how to get going while the battery is weak. Vehicle facts come from Hyundai's 2027 owner's manuals, read October 26, 2026.
CR2450smart key battery, 2027 manuals
3 stepsto replace it
Slim toolopens the rear cover
CR2032Elantra remote (folding) key
How do I replace the battery in my Hyundai key fob?
Insert a slim tool into the slot on the smart key and gently open the rear cover, remove the old battery and insert a new one, making sure it sits the right way up, then reinstall the rear cover. Hyundai's 2027 manuals list a CR2450 battery for the smart key. If the key still does not work, contact an authorized Hyundai dealer.
Which battery your Hyundai key takes
The battery type printed in each 2027 owner's manual we checked. Older Hyundai keys can differ, so check your own manual or the old battery before you buy.
| 2027 model | Key | Battery type |
|---|---|---|
| Santa Fe | Smart key | CR2450 |
| Tucson | Smart key | CR2450 |
| Kona | Smart key | CR2450 |
| Sonata | Smart key | CR2450 |
| Palisade | Smart key | CR2450 |
| Elantra | Smart key | CR2450 |
| Elantra | Remote (folding) key | CR2032 |
From the smart key and remote key battery sections of Hyundai's 2027 owner's manuals, posted on Hyundai's owners site and read October 26, 2026.
How to replace the smart key battery
The 2027 manuals give the same three steps for the smart key (the Elantra manual words step 1 as prying the cover open from the key hole):
- Insert a slim tool into the slot on the smart key and gently open the rear cover.
- Remove the old battery and insert the new one. Make sure the battery is the right way up: Hyundai says an improperly positioned battery may discharge it and cause the smart key to fail.
- Reinstall the rear cover of the smart key.
If you suspect the smart key is damaged, or it still is not working correctly, Hyundai says to contact an authorized Hyundai dealer. You can schedule service online with us.
Low battery message and other causes
Low key battery message
The 2027 Santa Fe, Tucson, Kona, Sonata and Palisade manuals say that when the Engine Start/Stop button is pressed to OFF, a message may appear indicating the smart key's internal battery is low. Replace the battery when you see it.
Interference can also stop the key
Not every key problem is the battery. Hyundai says the smart key may not work near a radio transmitter or a mobile phone, and that metallic window tint can reduce the smart key operating range.
Phone in the same pocket
The Santa Fe manual says an active phone can block the smart key's signal and suggests not keeping the key and phone in the same pocket.
How to start your Hyundai with a weak key battery
| 2027 model | What the manual says |
|---|---|
| Santa Fe, Tucson, Kona, Sonata | Press the Engine Start/Stop button with the smart key itself. |
| Palisade | Place the smart key in the smart key slot, then press the Engine Start/Stop button. |
| Elantra (push button start) | Press the Push Button Start ignition switch with the smart key. |
From the starting sections of the 2027 owner's manuals, read October 26, 2026. To get in, use the mechanical key; the manuals say it opens and closes the door when the smart key does not work correctly.
Coin battery safety
Every manual carries the same warning: the smart key contains a button battery, and a swallowed lithium button battery can cause severe or fatal injuries within 2 hours. Keep batteries out of reach of children, and get immediate medical attention if you think one has been swallowed or placed inside any part of the body.
Hyundai also says to dispose of used batteries according to local laws and regulations.
Michigan City Hyundai service hours
| Days | Hours |
|---|---|
| Monday to Friday | 7:30 a.m.-5 p.m. |
| Saturday | 7:30 a.m.-3 p.m. |
| Sunday | Closed |
From Michigan City Hyundai's website, October 26, 2026. Holiday hours can differ.
Vehicle battery, not the key? See our Hyundai battery service page.
Hyundai key fob battery FAQ
What battery does a Hyundai smart key take?
A CR2450 coin battery, according to the 2027 Santa Fe, Tucson, Kona, Sonata, Palisade and Elantra owner's manuals. The Elantra manual lists a CR2032 for its remote (folding) key.
How do I know my Hyundai key battery is low?
The 2027 Santa Fe, Tucson, Kona, Sonata and Palisade manuals say a message may appear when the Engine Start/Stop button is pressed to OFF, indicating the smart key's internal battery is low. When you see it, replace the battery.
Can I start my Hyundai if the key fob battery is weak?
Yes. If the smart key battery is weak, the 2027 Santa Fe, Tucson, Kona and Sonata manuals say to press the Engine Start/Stop button with the smart key itself, and the Elantra manual says to press the Push Button Start ignition switch with the smart key. The 2027 Palisade manual says to place the smart key in the smart key slot and then press the Engine Start/Stop button.
How do I get in if the key fob is dead?
Use the mechanical key. Hyundai's manuals say that if the smart key does not work correctly, you can open and close the door with the mechanical key.
Do I need the dealer to replace a Hyundai key battery?
No. The manual steps use a slim tool to open the rear cover. If the key still does not work after a new battery, or you think it is damaged, Hyundai says to contact an authorized Hyundai dealer, such as our service department.
Key still not working?
Visit Michigan City Hyundai at 625 US 20 in Michigan City, IN, and our service team can check the smart key or the vehicle battery.
Sources
Battery types, steps, messages and warnings are from Hyundai's 2027 Santa Fe, Tucson, Kona, Sonata, Palisade and Elantra owner's manuals, read October 26, 2026. Earlier model years can use different keys, so check your own manual. Address and hours are from Michigan City Hyundai's own website. Image: Hyundai Motor America.
- 2027 Santa Fe Owner's Manual: replacing the smart key battery, low key battery message, starting with a weak key, Hyundai Motor America, read October 26, 2026
- 2027 Tucson Owner's Manual: smart key battery and starting, Hyundai Motor America, read October 26, 2026
- 2027 Kona Owner's Manual: smart key battery and starting, Hyundai Motor America, read October 26, 2026
- 2027 Sonata Owner's Manual: smart key battery and starting, Hyundai Motor America, read October 26, 2026
- 2027 Palisade Owner's Manual: smart key battery and smart key slot, Hyundai Motor America, read October 26, 2026
- 2027 Elantra Owner's Manual: remote key and smart key batteries, Hyundai Motor America, read October 26, 2026
- Hyundai owner's manuals and warranties (manual downloads), Hyundai Motor America, read October 26, 2026
- Santa Fe (interior image), Hyundai Motor America, October 26, 2026
- Address and service hours (structured data), Michigan City Hyundai, October 26, 2026
- Hyundai service at Michigan City Hyundai, Michigan City Hyundai, October 26, 2026
