Open the key fob case to access the battery

Most Hyundai key fobs split into two halves along a seam that runs around the edge. Look for a small slot or groove on the side of the fob — this is where you insert a flathead screwdriver or a coin to pry the case apart. Insert the tool gently into the slot and twist slightly; the case will pop open without much force. Do not force it hard enough to crack the plastic.

Once the case is open, you will see the battery sitting in a small metal holder. The battery is typically a CR2032 or CR2025 coin cell, which is round and flat. Note which side faces up — the positive side (marked with a + symbol) should face toward you when you look at the open fob. This matters when you install the new battery.

Key Takeaways

  • Hyundai key fobs use a CR2032 or CR2025 coin cell battery that you can buy at any drugstore, supermarket, or hardware store for two to five dollars.
  • The fob case splits along a seam on the edge; use a flathead screwdriver or coin in the slot to gently pry it open without forcing it.
  • Note which side of the battery faces up before you remove it, so you install the new one the same way — positive side up.
  • The entire job takes less than two minutes and requires no tools beyond what you already have at home.
  • If the fob still does not work after you install a fresh battery, the problem is likely a worn contact or a broken circuit board, not the battery itself.

Remove the old battery and note its position

Gently pry the old battery out of its metal holder using your fingernail or the edge of a coin. The battery sits loosely in the holder and will come out with light pressure. Do not dig at it with a sharp tool, as you can damage the metal contacts inside the fob.

Before you set the old battery down, look at how it was positioned. The positive side (the flat side with the + mark) should have been facing up toward the open face of the fob. When you install the new battery, it must go in the same way. If you install it upside down, the fob will not work.

Buy the correct replacement battery

Take the old battery with you to the store so you can match it exactly. Most Hyundai fobs use a CR2032, which is the most common coin cell battery made. Some older models use a CR2025, which is slightly thinner but the same diameter. The package will say which type it is.

You can buy these batteries at any pharmacy, supermarket, big-box retailer, or hardware store. They cost between two and five dollars. Buy one extra battery while you are there — coin cells last three to four years in a key fob, and having a spare means you will not be caught without a working fob when the next one dies.

Install the new battery with the positive side up

Place the new battery into the metal holder with the positive side (the side marked +) facing up, toward the open face of the fob. The battery should sit flat and level in the holder. If it feels loose or tilted, remove it and try again — it should fit snugly without any rocking.

Do not force the battery into the holder. If it does not sit flat, you may have it upside down. Flip it over and try again. Once it is in place and level, you are ready to close the fob.

Close the fob case and test the buttons

Line up the two halves of the fob so the seam is even all the way around. Press the halves together firmly until you hear or feel a click. The case should snap shut without gaps. If it does not close all the way, the battery may be sitting too high — open it again and make sure the battery is flat in its holder.

Once the case is closed, test the fob by pressing each button while standing near your car. The lock and unlock buttons should work right away. If nothing happens, open the fob again and check that the battery is installed positive side up. If the battery is in the correct position and the fob still does not work, the problem is likely worn metal contacts or a broken circuit board inside the fob, not the battery itself.

What to do if the fob still does not work

If you installed a fresh battery and the fob buttons still do not respond, try cleaning the metal contacts inside the fob. Open the case again and look at the small metal circles where the battery sits. If they look dark or corroded, rub them gently with a clean, dry cloth or a pencil eraser. Corrosion can block the electrical connection even with a new battery.

If cleaning the contacts does not help, the circuit board inside the fob may be damaged. At that point, you will need to replace the entire fob. Contact a Hyundai dealership or a locksmith who works with car keys — they can order a replacement fob and program it to your car. The cost is usually between 100 and 300 dollars depending on your model year and whether the fob has extra features like a panic button.

Frequently Asked Questions

How long does a key fob battery last?

A CR2032 or CR2025 battery in a Hyundai key fob typically lasts three to four years with normal use. If you use the fob many times every day, the battery may wear out sooner. If you rarely use the fob, it may last longer. Extreme heat or cold can also shorten battery life.

Can I use a different type of battery?

No. Use only the exact battery type that came in your fob — either CR2032 or CR2025. Other coin cell batteries may have different voltage or size, and they will not work properly in your fob. Check the old battery or your owner's manual to confirm which type you need.

What if I cannot get the fob case open?

Try using a different tool — a coin often works better than a screwdriver because it is thinner and fits the slot more easily. Warm the fob slightly under warm running water for a few seconds; this can soften the plastic and make it easier to pry open. If the case is cracked or the slot is damaged, you may need a replacement fob.

Is it safe to handle the battery with my bare hands?

Yes. Coin cell batteries are safe to touch with bare hands. You do not need gloves. Just avoid getting the battery wet or exposing it to extreme heat, and do not try to take it apart or short the terminals together.

Do I need to reprogram the fob after changing the battery?

No. Changing the battery does not erase the fob's programming. Once you install the new battery and close the case, the fob should work when ready without any reprogramming steps.