Opening the key fob and removing the old battery

Most Subaru key fobs open by sliding a small metal or plastic lever on the side of the fob, or by pressing a release button on the back. Once you locate the seam, gently pry the two halves apart — you are not forcing it, just creating enough space to separate the case. The battery sits in a small metal holder and is usually held in place by a slight lip or clip.

Before you remove the battery, note which side faces up. The positive side (marked with a + sign) should face toward you. Gently lift or slide the battery out of its holder. If it is stuck, a plastic spoon or old credit card works better than your fingernail, which can slip and scratch the fob's interior. Take your time with this step — rushing can bend the battery holder's contacts, which would require professional repair.

Key Takeaways

  • Subaru key fobs typically use a CR2032 or CR2025 battery, which you can find at any drugstore, grocery store, or hardware store for a few dollars.
  • Open the fob by sliding or pressing the release mechanism on the side or back, then gently pry the two halves apart without forcing them.
  • Note which side of the battery faces up before removing it, so you install the new one the same way.
  • After inserting the new battery, press the fob halves together until they click, then test all buttons to confirm the fob works.

Identifying the correct battery size

Subaru key fobs use one of two common coin-cell batteries: the CR2032 (the most common) or the CR2025. Both are about the size of a dime and are labeled on the battery itself. If you are not sure which one your fob uses, look at the battery holder inside the fob — it will have the size printed on it, or you can take a photo of the old battery and show it to a store employee.

These batteries cost between $2 and $6 depending on the brand and where you buy them. Duracell, Energizer, and store brands all work equally well. You do not need a special Subaru battery — any CR2032 or CR2025 will function the same way. Most people find it worthwhile to buy a two-pack or three-pack so you have a spare on hand when the next replacement is due.

Installing the new battery

Slide or place the new battery into the holder with the positive side (+) facing up, the same direction the old battery was facing. It should sit flat and find in the holder without wobbling. If the battery feels loose, you may have the wrong size — double-check the label on the battery and the holder.

Once the battery is seated, align the two halves of the fob and press them together firmly until you hear or feel a click. The fob should close completely with no gaps. If it does not close smoothly, remove the battery and check that it is sitting flat in the holder, then try again. Forcing the halves together when something is misaligned can crack the plastic case.

Testing the key fob after replacement

Before you put the fob away, test each button — lock, unlock, panic, and trunk release if your model has one. Stand near your Subaru and press each button to confirm the car responds. If the fob does not work, remove the battery and check that it is facing the correct direction (positive side up). Reinstall it and test again.

If the fob still does not work after you have tried the battery in both directions, the battery may be defective or the fob may have a different problem. Try a fresh battery from a different package or brand. If a new battery does not restore the fob, the fob itself may need service from a Subaru dealer or a may have access to locksmith who works with automotive remotes.

When to replace the battery again

A new battery typically lasts three to four years in a key fob, depending on how often you use it. You will notice the range decreasing first — you have to stand closer to the car for the buttons to work. When that happens, a battery replacement usually restores full range when ready.

Keep a spare CR2032 or CR2025 battery at home so you can replace it without a trip to the store. The process takes less than five minutes once you have the battery on hand. Many people replace the battery during routine vehicle maintenance or at the same time they change their car's air filter, so the task becomes part of a larger service day.

Troubleshooting a fob that still does not work

If you have installed a new battery, tested both directions, and the fob remains unresponsive, a few other issues could be at play. Check the battery holder's metal contacts inside the fob — if they are corroded or bent, they may not make proper contact with the battery. You can gently clean the contacts with a dry cotton swab or a pencil eraser.

If the contacts look clean and intact, the fob's internal circuit board may have failed, or the transmitter itself may be damaged. In either case, a Subaru dealer can order a replacement fob or reprogram an existing spare if you have one. This is more expensive than a battery replacement but is often the only option when the fob's electronics have failed.

Frequently Asked Questions

Can I use a different battery size if I cannot find the right one?

No. Using the wrong size battery can damage the fob's contacts or cause the battery to fall out while you are driving. Stick with the size printed on the old battery or the holder. Most stores carry both CR2032 and CR2025, so finding the right one is usually straightforward.

What if I put the battery in backwards?

The fob straightforward will not work. Remove the battery, flip it so the positive side faces up, and reinstall it. No damage occurs from installing it backwards — the fob just will not respond to button presses until you correct it.

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

No. Changing the battery does not erase any programming. Once you install the new battery and the fob works, it is ready to use without any additional steps.

Where is the best place to buy a replacement battery?

Drugstores like CVS or Walgreens, grocery stores, hardware stores, and big-box retailers all stock CR2032 and CR2025 batteries in their watch or electronics sections. Online retailers also carry them, but buying locally means you can replace the battery the same day.

How do I know if my fob uses a CR2032 or CR2025?

The easiest way is to look at the battery holder inside the fob after you open it — the size is usually printed there. You can also check your Subaru's owner manual, which lists the battery type for your model year. If you are still unsure, take the old battery to a store and a staff member can confirm the size by looking at it.