You can replace a Subaru key fob battery yourself in about five minutes
Most Subaru key fobs use a coin-cell battery — usually a CR2032 or CR2025 — that you can buy at any drugstore, grocery store, or online retailer for two to five dollars. The fob itself doesn't need to go to a dealer. You open it with a flat tool, swap the old battery for the new one, and close it back up. The whole process takes longer to find the right screwdriver than to do the work.
The only thing that varies is how the fob opens. Some Subaru fobs have a slot on the edge where you slide a flat tool; others have a small screw you remove first. Once you know which type you have, the rest is straightforward.
Key Takeaways
- Subaru key fobs use CR2032 or CR2025 coin-cell batteries that cost two to five dollars and are sold at most retailers.
- You open the fob either by sliding a flat tool into an edge slot or by removing a small Phillips screw on the back.
- The battery sits in a metal holder; note which side faces up before you remove it, then install the new one the same way.
- After you close the fob, test it on your car before you put it away to confirm the new battery is working.
Identify which type of fob you have
Look at the back and edges of your key fob. If you see a small horizontal slot or seam running along one edge, your fob opens by sliding. If you see a small screw — usually Phillips-head — on the back, your fob opens by unscrewing.
Subaru fobs from roughly 2010 onward tend to be the sliding type, but this is not a hard rule. The easiest way to know for certain is to look at the back: if there's a screw, you'll see it. If there's no screw, the fob slides open.
Get the right battery and tools
Buy a CR2032 battery first. This is the most common size for Subaru fobs. If your fob doesn't work with a CR2032, you'll know when ready when you open it and see the battery is the wrong size — then you can swap it for a CR2025, which is slightly thinner. Both cost the same and are stocked at pharmacies, supermarkets, and online.
For tools, you need a flat object thin enough to fit into the fob's seam or slot. A flathead screwdriver works, but so does a butter knife, a coin, or even a plastic spoon handle. If your fob has a screw, use a Phillips screwdriver that fits the screw snugly — a screwdriver that's too large or too small will strip the screw head and make it harder to open next time.
Open the fob if it slides
Hold the fob in one hand with the back facing you. Locate the seam or slot running along the edge. Insert your flat tool into the slot and gently twist or pry. The fob will separate into two halves — the metal back and the plastic front. Don't force it; if it's not moving, you may have the tool in the wrong spot or at the wrong angle.
Once the fob is open, you'll see the battery sitting in a metal holder in the center. The holder has a small lip or edge that holds the battery in place. Don't lose this holder — you'll need it to install the new battery.
Open the fob if it has a screw
Hold the fob with the back facing you. Locate the small Phillips screw and use your screwdriver to remove it. Set the screw somewhere safe — a small dish or envelope works well. Once the screw is out, the back cover will slide or pop off, revealing the battery holder inside.
The battery sits in the same metal holder as the sliding type. Again, don't lose the holder itself — only the battery comes out.
Remove the old battery and install the new one
Look at the battery in the holder. One side will have a plus sign (+) printed on it; the other side is blank. This matters. Before you remove the old battery, note which side is facing up. Remove the old battery by gently prying it out with your flat tool or by hand if it's loose enough.
Take your new CR2032 battery and install it with the same side facing up as the old one was. If the plus sign was facing up before, the plus sign faces up now. If the blank side was facing up, the blank side faces up now. Press the battery down gently until it sits flat in the holder.
Close the fob and test it
If your fob slides open, press the two halves back together until they click or snap. You should hear or feel a small click when they're fully seated. If your fob has a screw, replace the screw and tighten it snugly — don't over-tighten, or you may strip it.
Before you put the fob away, test it on your car. Stand near your Subaru and press the lock and unlock buttons. You should hear the car respond or see the lights flash. If nothing happens, open the fob again and check that the battery is sitting flat in the holder and facing the right direction. If the battery is in correctly and the fob still doesn't work, the fob itself may have a problem unrelated to the battery.
Frequently Asked Questions
How do I know if my key fob battery is dead?
The buttons will stop responding, or you'll have to press them multiple times before the car reacts. The range will also shrink — you'll have to stand closer to the car for it to work. If the fob worked fine yesterday and stopped working today, the battery is almost certainly the culprit.
Can I use a different battery size if I can't find a CR2032?
A CR2025 will work as a substitute because it's the same width but slightly thinner. A CR2016 is too thin and may not make proper contact. Stick with CR2032 or CR2025 — both are common and inexpensive.
What if I can't get the fob open?
Make sure you're using a flat tool thin enough to fit the slot. If the fob has a screw, confirm the screwdriver fits the screw head snugly before turning — a loose fit will slip and damage the screw. If you're still stuck, a Subaru dealer can open it for you, though they'll charge a service fee.
Do I need to reprogram the fob after I replace the battery?
No. The fob stores its programming in a chip inside; the battery only powers it. Once you install a fresh battery, the fob will work exactly as it did before, with no reprogramming needed.
How long does a key fob battery last?
Most coin-cell 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 wear out sooner. There's no way to predict exactly when it will fail, so replace it as soon as the fob stops responding reliably.