You can replace a Honda key fob battery yourself in about two minutes with a coin
Most Honda key fobs use a coin-cell battery — typically a CR2032 or CR2025 — that you can swap out without tools or a trip to the dealer. The battery sits behind a removable cover on the back of the fob. You pry the cover open with a coin or flat object, slide out the old battery, and slide in a new one. The whole job takes longer to find the battery than to install it.
The exact steps depend on which Honda model and fob design you own, because Honda has used several different fob shells over the years. Some have a seam you can pry open; others have a small slot you insert a coin into. This guide covers the most common designs you will encounter.
Key Takeaways
- Honda key fobs almost always use a CR2032 or CR2025 coin-cell battery that you can buy at any pharmacy, supermarket, or hardware store for a few dollars.
- The battery sits in a compartment on the back of the fob behind a removable cover that opens with a coin or flat object — no screwdriver needed.
- Before you open the fob, note which way the battery sits (the side facing you) so you can install the new one the same way.
- If your fob still does not work after you replace the battery, the problem is usually a worn contact inside the fob rather than a dead battery.
What battery your Honda key fob uses
Honda key fobs use one of two coin-cell batteries: the CR2032 or the CR2025. The CR2032 is thicker and more common; the CR2025 is slightly thinner. Both are 20 millimeters in diameter. You can find either at a pharmacy, supermarket, grocery store, or hardware store — they cost between two and five dollars. Some dollar stores and gas stations carry them too.
If you are not sure which one your fob uses, open the fob first and look at the battery itself. The battery will have a number printed on it. Write that number down and buy the same one. You can also call a Honda dealership parts department with your vehicle identification number (VIN) and model year, and they will tell you which battery your fob uses — but you will pay more if you buy it from them.
Do not buy a generic "key fob battery" pack without checking the model number. The wrong size will not fit or will fall out when you close the fob.
How to open the fob and remove the old battery
The most common Honda fob design has a seam running around the edge of the back cover. To open it, hold the fob in one hand with the buttons facing away from you. Take a coin — a penny, dime, or quarter works — and insert it into the seam at the bottom of the fob. Twist the coin gently to pry the cover up. The cover will pop off, and you will see the battery sitting in a small metal holder.
Some newer Honda fobs have a small slot instead of a seam. Look for a thin line or notch on the back of the fob. Insert a coin into the slot and twist gently. The cover will slide or pop off the same way.
Once the cover is off, look at how the battery is sitting in the holder. The side facing you is the positive side (marked with a + symbol). Note which side is facing up. Then gently pry the battery out with your coin or a fingernail. Do not force it — it should come out with light pressure.
Installing the new battery and closing the fob
Take your new battery and place it in the holder with the same side facing up as the old battery was. The positive side (the + symbol) should face the same direction. Press down gently until you hear or feel a small click — the battery will sit flat in the holder.
Now close the fob by pressing the cover back on. Line up the seam or slot with the body of the fob and press down firmly until you hear a click and the cover sits flush. The fob should feel solid when you squeeze it gently.
Test the fob by pressing each button — lock, unlock, and panic if your model has one. The lights on the fob should flash, and your car should respond. If nothing happens, open the fob again and check that the battery is sitting flat in the holder and facing the right direction.
What to do if the fob still does not work after replacing the battery
If you installed a new battery and the fob still does not work, the problem is usually not the battery. The metal contacts inside the fob can wear out or corrode over time, especially if the fob has been dropped or exposed to moisture. Replacing the battery will not fix a worn contact.
You have two options: buy a replacement fob from Honda (the dealership can order one and program it to your car), or try cleaning the contacts inside the fob. To clean the contacts, open the fob again and look for two small metal strips inside the cover. Rub them gently with a pencil eraser or a dry cloth to remove any corrosion. Close the fob and test it again.
If cleaning does not work, the fob itself has failed and needs to be replaced. A new OEM Honda fob costs between 150 and 300 dollars depending on the model, plus programming fees at the dealership. Some independent locksmiths can program aftermarket fobs for less.
How often you need to replace the battery
A Honda key fob battery usually lasts between three and four years with normal use. If you use the fob heavily — pressing the buttons many times a day — the battery may wear out sooner. If you use it lightly, it may last longer.
You will notice the fob starting to fail before the battery is completely dead. The buttons may require harder presses, or the range may get shorter — you have to stand closer to the car for it to respond. When you see these signs, replace the battery. Do not wait until the fob stops working entirely, because you may be locked out of your car.
Frequently Asked Questions
Can I use a different battery size if I cannot find the exact one?
No. The CR2032 and CR2025 are different thicknesses, and using the wrong one will either not fit or will rattle inside the fob and lose contact with the holder. Always use the exact battery model printed on the old battery or listed in your owner's manual.
Do I need to reprogram the fob after I replace the battery?
No. Replacing the battery does not erase the fob's programming. Once you install the new battery and close the fob, it should work when ready without any reprogramming steps.
What if I drop the battery or lose it while opening the fob?
Coin-cell batteries are small and straightforward to lose. Open the fob over a table or towel so the battery does not roll away. If you lose it, you will need to buy a new one, but they are inexpensive and widely available.
Can I replace the battery in a Honda fob that has a physical key inside?
Yes. Some Honda fobs have a metal key that slides out from the side or bottom. The battery compartment is still on the back of the fob. Slide the key out first if it gets in your way, then open the fob and replace the battery the same way.
Is it safe to handle a coin-cell battery with my bare hands?
Yes. Coin-cell batteries are safe to touch. They produce very little current and will not shock you. Wash your hands after handling one if you have sensitive skin, but there is no danger from normal contact.