You can replace a Toyota key fob battery yourself in about five minutes
Most Toyota key fobs use a coin-cell battery—usually a CR2032 or CR2025—that you can buy at any drugstore, grocery store, or hardware store for a few dollars. The battery sits behind a removable cover on the back of the fob. You do not need any tools beyond a coin or your fingernail to open it. The whole job takes longer to find the battery in your junk drawer than to swap it out.
The exact steps depend slightly on which Toyota model you own, because the fob design changed over the years. But the principle is the same: pry open the back, note which side of the battery faces up, slide out the old one, and slide in the new one the same way.
Key Takeaways
- Toyota key fobs almost always use a CR2032 or CR2025 coin-cell battery, which costs two to five dollars and is sold everywhere.
- You open the fob by sliding a coin into the slot on the back edge or by prying gently with a flathead screwdriver—no special tools needed.
- The battery has a + side and a − side; note which way it faces before you remove it, then install the new battery the same way.
- If the fob still does not work after you replace the battery, the problem is usually a worn contact or a dead circuit board, not the battery itself.
Finding the right battery for your Toyota fob
Before you open the fob, you need to know which battery it takes. The easiest way is to look at the back of the fob itself. Most Toyota fobs have the battery type printed or stamped on the plastic case—you may see "CR2032" or "CR2025" printed there. If you cannot read it, you can also open the fob first, take out the old battery, and read the number on the battery itself.
CR2032 is by far the most common. CR2025 is slightly thinner but works the same way. Both are sold in multipacks at drugstores, supermarkets, Walmart, Target, and online retailers. Buy a pack of two or four so you have a spare when the next one dies—key fob batteries typically last three to four years.
Opening the fob without damaging it
Look at the back edge of your key fob. You will see a small slot or seam running horizontally across the back. This is where the two halves of the fob meet. Slide a coin—a dime or penny works fine—into that slot and gently twist it like you are opening a paint can. The back cover will pop off. If there is no slot, you can use a flathead screwdriver instead, but go slowly and do not force it, or you will crack the plastic.
Once the back is off, you will see the battery sitting in a small metal holder. The battery is round and flat, about the size of a dime. Do not lose the rubber gasket or any small springs if they come loose—they keep moisture out of the fob.
Removing and replacing the battery
Before you touch the old battery, look at which side is facing up. The + symbol should be facing either toward you or away from you—note this. Slide the old battery out of its holder. It may come out easily, or you may need to gently pry one edge with a coin or your fingernail.
Take your new battery and slide it into the holder the same way the old one was facing. The + side must face the same direction. If you put it in backward, the fob will not work, but you can straightforward flip it and try again—the battery will not be damaged.
Once the battery is in, press the back cover back onto the fob until you hear or feel a click. Test the fob by pressing each button—the lock and unlock buttons should work right away. If nothing happens, open it back up and check that the battery is facing the right way.
What to do if the fob still does not work
If you installed a fresh battery and the fob still does not respond, the problem is not the battery. The most common culprit is a worn contact inside the fob. Over time, the metal contacts that touch the battery can corrode or wear down, breaking the electrical connection. You can try cleaning the contacts with a pencil eraser or a cotton swab dipped in rubbing alcohol, then reinstalling the battery.
If cleaning does not help, the circuit board inside the fob may be dead. This is rare, but it happens. At that point, you will need to have the fob reprogrammed or replaced by a Toyota dealer. Call your local dealer and ask what they charge to replace a key fob battery and reprogram it if needed—prices vary by location, but expect to pay more than you would for a battery alone.
Keeping your key fob working longer
Key fob batteries die because they are always on, even when you are not using the fob. The radio receiver inside is always listening for a signal from your car. You cannot stop this, but you can slow it down by keeping the fob away from heat and moisture. Do not leave it in direct sunlight, in a hot car, or in a pocket where it gets wet. Store it in a cool, dry place when you are not using it.
If you have an older Toyota fob that is starting to feel loose or rattle, the battery holder may be wearing out. When that happens, even a new battery may not make good contact. Again, a Toyota dealer can replace the fob or repair the holder, but it is usually cheaper to buy a new aftermarket fob online and have it programmed by the dealer.
Frequently Asked Questions
Can I use a different battery size if I cannot find a CR2032?
No. CR2032 and CR2025 are not interchangeable with other sizes. CR2025 is thinner, and CR2016 is even thinner—they will not fit properly in the holder or make good contact. Stick with the size printed on your fob or the old battery. Most stores carry CR2032 in stock.
Do I need to reprogram the fob after I replace the battery?
No. Replacing the battery does not erase the fob's programming. As soon as you install the new battery, the fob should work exactly as it did before. If it does not, the problem is the battery orientation or a worn contact, not the programming.
How long does a new key fob battery last?
Most Toyota key fob batteries last three to four years with normal use. If you use the fob heavily—pressing the buttons many times a day—it may die sooner. If you use it rarely, it may last longer. The battery will eventually die even if you never use the fob, because the receiver inside is always powered on.
What should I do with the old battery?
Coin-cell batteries contain small amounts of lithium and should not go in the trash. Take them to a battery recycling program. Most Best Buy locations, Lowe's, and Home Depot accept old batteries for free. You can also search Earth911.com to find a recycling center near you.
Can I buy a replacement fob instead of replacing the battery?
Yes. Aftermarket key fobs for Toyota are sold online and at some auto parts stores for twenty to fifty dollars, depending on the model year. You will need to have a Toyota dealer or a locksmith program it to your car, which usually costs fifty to one hundred dollars. For most people, replacing the battery is cheaper and faster.