You can replace a Hyundai key fob battery yourself in about five minutes
Most Hyundai key fobs use a coin-cell battery—usually a CR2032, CR2025, or CR2016—that you can buy at any drugstore, supermarket, or hardware store for two to five dollars. The battery typically lasts three to four years before the fob stops locking or unlocking your car reliably. You do not need tools or a dealer visit; you just need to open the fob, swap the old battery for a new one, and snap it shut.
The exact steps depend on whether your fob has a slide-out key blade or a push-button design, but both types open the same way: by prying the two halves apart along the seam. Once inside, you will see the battery sitting in a small metal holder. Note which side faces up, remove the old battery, drop in the new one the same way, and close the fob. Test it on your car before you leave.
Key Takeaways
- Hyundai key fobs use a coin-cell battery, most commonly CR2032, that costs two to five dollars and lasts three to four years.
- You open the fob by sliding a flat tool (coin, flathead screwdriver, or plastic pry tool) into the seam between the two halves and gently twisting to separate them.
- The battery sits in a metal holder inside; note which side faces up before you remove it so you can install the new one the same way.
- After closing the fob, test the lock and unlock buttons on your car to confirm the new battery is working before you drive.
Identify your battery type before you buy
Hyundai uses three common coin-cell batteries depending on the model year and fob design. The CR2032 is the most common—it is slightly thicker than a dime and appears in most recent Hyundai fobs. The CR2025 is thinner and shows up in some older models. The CR2016 is the thinnest and less common but still used in a few fob versions.
You can find the battery type printed on the inside of your fob once you open it, or you can check your owner's manual. If you are unsure, take your old battery to the store and match it by size and the printed code on top. All three types cost about the same and are stocked everywhere batteries are sold.
Open the fob without damaging the plastic
Locate the seam that runs around the edge of your fob—it separates the front and back halves. Slide a flat, thin object into the seam: a coin works well, or a plastic pry tool, or a small flathead screwdriver. Do not use a knife or anything sharp that could slip and cut you.
Once the tool is in the seam, twist it gently to create a small gap. Work your way around the edge, inserting the tool at different points and twisting slightly each time. The two halves will separate without much force—if you are straining hard, you are probably using too much pressure. Once there is a gap wide enough to fit your fingernail, you can usually pry the rest open by hand.
Remove the old battery and install the new one
Inside the fob you will see the battery sitting in a small metal holder or clip. Before you touch it, look at which side is facing up—the positive side (marked with a + symbol) or the negative side (marked with a − symbol). This matters because the battery will not work if it is installed backwards.
Gently pry the old battery out of the holder using your fingernail or the edge of a coin. Drop the new battery into the same holder with the same side facing up. It should sit flat and snug. If it is loose or tilted, remove it and try again—a properly seated battery will not rattle.
Close the fob and test it
Line up the two halves of the fob so the seam is even all the way around. Press them together firmly until you hear or feel a click. The fob should be solid and not flex when you squeeze it gently. If there is a gap or it feels loose, open it again and make sure the battery is seated properly and nothing is blocking the seam.
Stand near your car and press the lock button on the fob. You should hear the doors lock and see the lights flash. Press unlock and confirm the doors unlock. If nothing happens, open the fob again and check that the battery is facing the right direction. If the fob still does not work after you flip the battery, the battery itself may be defective—try a fresh one from a different package.
When to take your fob to a dealer
If you have replaced the battery and the fob still does not work, the problem is likely inside the fob itself—a broken button contact, a cracked circuit board, or a loose wire. These are not field repairs; you will need a replacement fob from a Hyundai dealer or a third-party fob programmer. Expect to pay between fifty and two hundred dollars depending on your model year and whether you buy an OEM (original equipment manufacturer) fob or an aftermarket one.
If your car does not respond to the fob even though the buttons work and the battery is new, the receiver in your car may need attention. This is rare, but it can happen if the car's battery has been disconnected or if there is a fault in the vehicle's electrical system. A dealer can diagnose this with a scan tool.
Frequently Asked Questions
Can I use a different battery type if I cannot find the exact one?
No. CR2032, CR2025, and CR2016 are different thicknesses and will not fit properly or work reliably in a fob designed for a different size. Buy the correct type for your fob—it is printed inside once you open it, and any store that sells batteries can match it for you.
How do I know which side of the battery goes up?
Look at the battery holder inside the fob before you remove the old battery. The positive side (marked +) usually faces up toward the circuit board, but check your specific fob to be sure. Take a photo of the old battery in place if you are unsure, then match it exactly when you install the new one.
What if the fob still does not work after I replace the battery?
First, open the fob and flip the battery around—it may be installed backwards. If that does not work, try a fresh battery from a different package in case the first one was defective. If the fob still does not respond, the problem is inside the fob itself and you will need a replacement from a Hyundai dealer.
Can I replace the battery in a smart key or push-button fob the same way?
Yes. Smart keys and push-button fobs open the same way as traditional fobs—pry along the seam with a flat tool. The battery location and replacement process are identical. The only difference is the button design on the outside, not the inside.
How often do I need to replace the battery?
Most Hyundai key fob batteries last three to four years with normal use. If you use your fob frequently or live in a very hot climate, the battery may wear out sooner. Replace it as soon as the lock or unlock buttons stop working reliably.