You can replace a Subaru key fob battery yourself in under five minutes
Most Subaru key fobs use a coin-cell battery — usually CR2032 or CR2025 — that you can buy at any drugstore or supermarket for two to five dollars. The fob itself splits open with a flathead screwdriver or coin, the old battery slides out, and a new one slides in. You do not need to visit a dealer or pay a technician. The whole job takes longer to find the right screwdriver than to do the work.
The exact steps depend slightly on which Subaru model and fob generation you own, but the principle is the same across all of them. This guide covers the most common design — the horizontal-split fob that opens like a clamshell — and notes where other designs differ.
Key Takeaways
- Subaru key fobs almost always use CR2032 or CR2025 coin-cell batteries, which cost two to five dollars and are sold at pharmacies, supermarkets, and hardware stores.
- A small flathead screwdriver or the edge of a coin inserted into the slot on the fob's spine will pry the two halves apart without damage.
- The battery sits in a metal holder and slides out horizontally; note which side faces up before you remove it so you can install the new one the same way.
- After you insert the new battery, press the fob halves together until they click, then test the lock and unlock buttons before you leave the store or your home.
What battery your Subaru key fob needs
The vast majority of Subaru key fobs from the 2000s onward use either a CR2032 or CR2025 coin-cell battery. The CR2032 is slightly thicker and holds a bit more charge; the CR2025 is thinner. Both are 20 millimeters in diameter. If you are not sure which one your fob takes, look inside the battery compartment after you open it — the battery itself will be stamped with the model number.
You can buy either battery at a pharmacy (CVS, Walgreens), a supermarket, a hardware store, or online. A pack of two or four costs between two and five dollars. Some Subaru dealers sell them too, but there is no reason to pay dealer prices for a commodity battery.
If your fob is very old — pre-2000 — or if you have an unusual remote start fob, check your owner's manual or call your local Subaru dealer to confirm the battery type before you buy. Putting the wrong battery in will not damage the fob, but it will not work.
How to open your Subaru key fob
Look at the spine of your fob — the edge where the two halves meet. You will see a small slot or seam running along it. This is where the fob splits. Take a flathead screwdriver (a small one, roughly the size of a dime) or the edge of a coin and insert it gently into that slot. Do not force it; you are not prying hard, just creating enough pressure to separate the two halves.
Twist the screwdriver or coin slightly, as if you were opening a paint can. The two halves will start to separate. Once there is a gap, you can usually pull the halves apart by hand. If the fob is stuck, try a different spot along the seam — sometimes one end opens more easily than the other.
Be gentle. The plastic is durable, but aggressive prying can crack the casing or snap the internal clips that hold the halves together. If you feel strong resistance, stop and try a different approach rather than forcing it.
Removing and replacing the battery
Once the fob is open, you will see the battery sitting in a metal holder or clip. It is usually in the center of the fob, and it will be a small, flat, silver coin. Before you touch it, note which side is facing up — the positive side (marked with a +) or the negative side (marked with a −). This matters.
Slide the battery out of its holder. It should come free easily; if it does not, check whether there is a small metal tab or clip holding it in place. Some fobs have a tiny clip you need to lift slightly to release the battery. Once the old battery is out, slide the new battery in the same way, making sure the positive side faces the same direction as the old one did.
If you installed the battery backwards, the fob straightforward will not work — the buttons will not respond. It will not damage the fob or the battery. If the buttons do not work after you close the fob, open it again and flip the battery 180 degrees.
Closing the fob and testing it
Align the two halves of the fob so the seams match up evenly. Press them together firmly until you hear or feel a click. The fob should be snug and not rattle. If there is a gap or the halves do not sit flush, open it again and check that the battery is seated properly and that no internal parts are in the way.
Once the fob is closed, test the lock and unlock buttons. Point the fob at your Subaru from a few feet away and press each button. You should see the lights flash and hear the locks engage. If nothing happens, the battery is probably installed backwards — open the fob again and flip it.
If the buttons still do not work after you flip the battery, the new battery may be defective (rare) or the fob itself may have a problem unrelated to the battery. Try a different new battery from a different package if you have one. If that does not work, the fob's internal circuitry may need service, and you will need to contact a Subaru dealer or a locksmith.
Fobs with a different design
Some Subaru fobs, particularly older models and some remote start fobs, open differently. Instead of a horizontal split, they may have a vertical seam or a small screw on the back. If your fob has a screw, use a small Phillips or flathead screwdriver (depending on the screw type) to remove it, then gently pry the halves apart.
A few high-end remote start fobs have a more complex design with multiple compartments. If you cannot find the battery compartment after opening the fob, or if the fob does not open easily, consult your owner's manual or contact a Subaru dealer. Forcing an unfamiliar design can break internal components.
When to replace your key fob battery
You will know the battery is dying when the buttons require multiple presses to work, or when the fob only works from very close to the car. A completely dead battery means the buttons do nothing at all. Some cars will also display a low-battery warning on the dashboard when the fob battery is weak.
You do not have to wait until the fob stops working entirely. If you notice it is getting sluggish, replacing the battery is cheap and takes minutes. Keep a spare CR2032 or CR2025 in your home or car so you are not caught with a dead fob when you need it.
Frequently Asked Questions
Can I use a different battery type if I cannot find CR2032?
CR2032 and CR2025 are not interchangeable with other battery types. CR2025 is slightly thinner than CR2032, and using the wrong one may cause fit problems or poor contact. Stick with the correct type. Most stores that sell batteries carry both, and they cost the same.
What do I do with the old battery?
Coin-cell batteries are recyclable and should not go in the trash. Take the old battery to a pharmacy, supermarket, or electronics store — most have a battery recycling bin near the checkout or customer service desk. Some accept them free; others may charge a small fee.
Will the fob lose its programming if I remove the battery?
No. The fob's programming is stored in a separate chip that does not depend on the battery. Removing the battery for a few minutes will not erase anything. You can safely take your time opening the fob and replacing the battery without worry.
What if the fob still does not work after I replace the battery?
First, make sure the battery is installed with the positive side facing the correct direction — open the fob and flip it if needed. 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 internal circuitry may be damaged, and you will need to contact a Subaru dealer or a locksmith for repair or replacement.
Can I replace the battery in a smart key or push-button fob?
Yes, the process is the same. Smart keys and push-button fobs use the same CR2032 or CR2025 batteries and open the same way. The only difference is the shape of the fob itself, but the battery compartment works identically.