You can replace a Hyundai key fob battery yourself in under five minutes
Most Hyundai key fobs use a coin-cell battery—usually a CR2032 or CR2025—that you can swap out without tools or a trip to the dealer. The battery typically lasts three to four years depending on how often you use the fob. When your fob stops locking or unlocking the car reliably, or the buttons feel sluggish, a dead battery is almost always the cause.
The process is straightforward: you pry open the fob case, remove the old battery, drop in a new one, and snap it shut. You do not need to reprogram anything. The new battery will work when ready.
Key Takeaways
- Hyundai key fobs use a CR2032 or CR2025 coin-cell battery that you can buy at any pharmacy, grocery store, or hardware store for $3 to $8.
- You can open the fob with a coin, a flathead screwdriver, or even a fingernail—there is a slot designed for prying.
- No reprogramming is needed after you install the new battery; the fob will work as soon as you close it.
- If the fob still does not work after a new battery, the circuit board or buttons may be damaged and you will need a replacement fob from a Hyundai dealer.
What battery your Hyundai key fob uses
Hyundai key fobs from the past 15 years almost always use either a CR2032 or CR2025 coin-cell battery. Both are 3-volt lithium batteries about the size of a dime. The CR2032 is slightly thicker and lasts a bit longer, but either will work in most Hyundai fobs—the fob case is designed to hold both.
You can check which one your fob needs by looking at the back of the fob case. Some models have the battery type printed there. If not, buy a CR2032; it is the most common and will fit. You can find these batteries at any pharmacy (CVS, Walgreens), grocery store, Target, Walmart, or hardware store. They cost between $3 and $8 for a single battery, or $5 to $15 for a pack of two or four.
How to open your key fob
Look at the edge of your key fob for a small slot or seam running around the perimeter. This is where the two halves of the case meet. You will see a thin line where you can insert something flat to pry them apart.
Use a coin (a penny or dime works well), a flathead screwdriver, or even a plastic spoon handle. Insert it into the slot and gently twist or lever it to separate the two halves. Do not force it—the case is plastic and will crack if you pry too hard. Work your way around the edge if the first spot does not budge; sometimes one side opens more easily than the other.
Once the case cracks open, you can pull the two halves apart by hand. Inside you will see the circuit board and the battery sitting in a small metal holder or clip.
Removing the old battery and installing the new one
The battery sits in a metal clip or holder on the circuit board. It may be held in place by the clip alone, or there may be a small piece of tape over it. If there is tape, gently peel it back.
Use your fingernail or the edge of a coin to pop the battery out of the clip. It will come out easily—do not pry hard. Drop the new battery into the same spot, making sure the flat side (marked with a + or −) faces the same direction as the old one did. The battery should sit flat in the clip and not wobble.
If there was tape over the old battery, you can put a small piece of new tape over the new one, though it is not required. The clip alone will hold it in place.
Closing the fob and testing it
Line up the two halves of the case so the seams match. Press them together firmly until you hear or feel a click. You may need to explore pressure at several points around the edge to make sure both halves snap together evenly.
Once the case is closed, test the fob when ready. Press the lock and unlock buttons while standing near your car. The lights on the dashboard should flash and you should hear the locks engage. If the fob works, you are done. If it does not, open the fob again and check that the battery is seated correctly in the clip and facing the right direction.
When the fob still does not work after a new battery
If you installed a fresh battery and the fob still does not respond, the problem is not the battery. The circuit board may have failed, or the rubber button pad underneath the buttons may have worn out. Both of these issues require a replacement fob.
You can buy a replacement fob from a Hyundai dealer, or you can buy an aftermarket fob online and have a dealer or locksmith program it to your car. Dealer fobs typically cost $150 to $300 and come programmed. Aftermarket fobs are cheaper but require programming, which adds another $50 to $150 in labor. If your original fob is still under your car's warranty, the dealer may replace it at no cost.
How to know when your battery is dying
A dying key fob battery does not usually fail all at once. Instead, you will notice the buttons becoming less responsive. You may have to press the lock button twice, or you may have to stand closer to the car for it to work. The range shrinks as the battery weakens.
Some fobs have a small LED light that flashes when you press a button. If that light is dim or does not flash at all, the battery is low. Once you notice these signs, replace the battery within a week or two. Waiting too long means you might get locked out if the fob dies completely before you have a chance to change it.
Frequently Asked Questions
Can I use a different battery size if I cannot find a CR2032?
A CR2025 will work in most Hyundai fobs, though it is slightly thinner. The fob case is designed to hold both sizes. Do not use a battery with a different voltage (like a 1.5-volt alkaline battery)—it will damage the circuit board. Stick to 3-volt lithium coin cells.
Do I need to reprogram my key fob after changing the battery?
No. The fob does not store any programming information in the battery. Once you install the new battery and close the case, the fob will work when ready without any reprogramming steps.
What should I do with the old battery?
Lithium coin-cell batteries can be recycled. Many pharmacies and electronics stores (Best Buy, for example) have battery recycling bins near the checkout. You can also check Earth911.com to find a recycling location near you. Do not throw it in the trash.
How long does a new battery last in a Hyundai key fob?
Most CR2032 batteries last three to four years in a key fob, depending on how often you use it. If you use your fob multiple times a day, the battery may last closer to two or three years. Light users may get four or five years.
Can I damage my car by opening the key fob?
No. The key fob is a separate device that communicates wirelessly with your car. Opening it and changing the battery will not affect your car's systems or void any warranty. Just be gentle when prying it open so you do not crack the plastic case.