What you need to know before you start
A Hyundai key fob with a fixed (non-folding) key blade uses a coin-cell battery that typically lasts three to four years. When the battery dies, the remote buttons stop working, but your physical key still opens the door and starts the car — so you are not locked out. Replacing the battery yourself takes about five minutes and costs between $3 and $8 for the replacement cell.
The exact battery type depends on your Hyundai model year and fob design. Most recent Hyundai fobs use a CR2032 battery, but some older models use CR2025 or CR2016. You will know which one you need once you open the fob. The process is straightforward: pry the fob open, remove the old battery, note which side faces up, insert the new one the same way, and snap it closed.
Key Takeaways
- Most Hyundai key fobs with a fixed key use a CR2032 coin-cell battery that you can buy at any drugstore, supermarket, or hardware store for a few dollars.
- You open the fob by inserting a flat tool (coin, flathead screwdriver, or plastic pry tool) into the seam and gently twisting to separate the two halves.
- The battery sits in a small metal holder; note which side faces up before you remove it, then insert the new battery the same way.
- If the buttons still do not work after you replace the battery, the fob may have water damage or a broken circuit board, and you will need a replacement fob from a dealer or third-party seller.
Identifying your battery type before you buy
You do not have to guess which battery your fob needs. Open the fob first, see what is inside, and then buy the right cell. This takes one minute and saves a return trip if you guess wrong.
To open the fob, look for a thin seam running around the edge where the two plastic halves meet. Insert a flat tool — a coin, a flathead screwdriver, or a plastic pry tool — into that seam and gently twist. The two halves will separate. Do not force it; if it does not budge, try a different spot along the seam. Once open, you will see a small metal battery holder with a coin-shaped cell inside. The cell itself is stamped with its type: CR2032, CR2025, or CR2016. Write down the number, close the fob, and go buy that exact battery.
Where to buy the replacement battery
Coin-cell batteries are sold almost everywhere. Drugstores like CVS and Walgreens stock them in the electronics or watch section. Supermarkets often carry them near the pharmacy or in the health and beauty aisle. Hardware stores like Home Depot and Lowe's have them in the electrical section. Walmart and Target sell them in electronics. Online, Amazon and eBay have them, but you will pay for shipping on a $3 item.
Buy a name-brand battery — Energizer, Duracell, Panasonic, or Sony — rather than a generic store brand. The difference in price is usually 50 cents, and name brands last longer and are less likely to leak inside your fob. If you are buying online, look for a pack of two or four; the extra batteries cost almost nothing more and you will have spares for other devices.
Opening the fob and removing the old battery
Once you have the new battery, open the fob again using the same seam-and-twist method. This time, you are removing the old cell. The battery sits in a small metal holder that clips or snaps into place. Look at which side of the battery faces up — the flat side or the side with the raised bump. This matters: the new battery must go in the same way.
Gently pry the old battery out of its holder using a fingernail or the edge of a plastic tool. Do not use a metal screwdriver directly on the battery; you can scratch it or cause a short. Once the old battery is out, set it aside. Do not throw it away yet — keep it in case you need to check the type number again.
Installing the new battery and closing the fob
Take the new battery and orient it the same way the old one was facing. If the flat side was up, the flat side goes up. If the raised bump was up, the bump goes up. Gently press the new battery into the metal holder until you hear or feel a small click. It should sit flush with the holder, not sticking up.
Now close the fob by pressing the two halves together. Align the seam so the edges line up evenly, then press down firmly until you hear a click. The fob should feel solid and not rattle. Test the buttons: press the lock, unlock, and panic buttons a few times. If they work, you are done. If they do not, try removing the battery and reinserting it to make sure it is seated properly. If the buttons still do not respond, the problem is not the battery.
What to do if the buttons still do not work
If you replaced the battery and the buttons are still dead, the issue is likely water damage, a corroded battery contact, or a broken circuit board inside the fob. Water damage is common if the fob has been dropped in water or exposed to heavy rain. Corrosion happens when an old battery leaks inside the fob and eats away at the metal contacts.
You have two options: buy a replacement fob or have a dealer program a used one. A new OEM (original equipment manufacturer) fob from a Hyundai dealer costs $150 to $300 and includes programming. A third-party replacement fob from Amazon or eBay costs $30 to $80 and usually comes with programming instructions or a link to a YouTube video showing how to program it yourself. Some third-party fobs require a dealer to program them; check the product listing before you buy. If you choose a used fob from a salvage yard or online marketplace, you will need a dealer to reprogram it to your car, which costs $50 to $150.
Keeping your fob in good condition
A key fob lasts longer when you keep it dry and avoid dropping it. Store it in a pocket or bag away from extreme heat or cold. If you drop it in water, remove the battery when ready, dry the inside with a soft cloth, and let it air-dry for 24 hours before reinserting the battery. If water got inside, the contacts may corrode even after drying, so be prepared to replace the fob.
Replace the battery every three to four years even if the buttons still work. An aging battery can leak inside the fob and damage the circuit board, which is expensive to repair. Replacing it on schedule is cheap insurance.
Frequently Asked Questions
Can I use a different battery type if I cannot find the exact one?
No. CR2032, CR2025, and CR2016 are different sizes and voltages. Using the wrong type may not fit the holder, or it may fit but not power the buttons. Buy the exact type stamped on your old battery.
Does the fob need to be reprogrammed after I change the battery?
No. Changing the battery does not erase the fob's programming. The buttons should work when ready after you close the fob. If they do not, the problem is not the battery.
What if I lose the old battery before I can read the type number?
Open the fob anyway and look at the metal battery holder. The holder is sized for a specific battery type, and the size difference between CR2032, CR2025, and CR2016 is visible. A CR2032 is noticeably thicker than the others. You can also take a photo of the empty holder and show it to a store employee; they can usually tell you which battery fits.
Is it safe to replace the battery myself, or should I go to a dealer?
It is safe to do yourself. You are only handling a small battery and plastic parts. A dealer will charge $50 to $100 to do the same five-minute job. The only reason to go to a dealer is if the fob is damaged or the buttons do not work after you replace the battery.