Open the fob and swap the battery yourself

You can replace a Subaru key fob battery in about five minutes with no tools except a coin or flathead screwdriver. The battery is a standard CR2032 (a round, flat cell about the size of a dime), which costs $3 to $8 at any pharmacy, grocery store, or hardware store. Most Subaru fobs use the same battery type regardless of model year, though a few older models use CR2025 instead—check your owner's manual or the fob itself to be sure.

The hardest part is opening the fob without breaking the plastic. Subaru fobs have a seam running around the edge where the two halves meet. You will insert your coin or screwdriver into that seam and gently twist to separate them. The battery sits in a small metal holder on one half. Once you see it, note which side faces up (the flat side or the domed side), remove the old battery, drop in the new one the same way, and snap the fob back together. Test it on your car before you leave the parking lot.

Key Takeaways

  • Subaru key fobs use a CR2032 battery, which you can buy at any pharmacy or grocery store for under $10.
  • Insert a coin or flathead screwdriver into the seam around the fob's edge and twist gently to open the two halves.
  • Note which side of the battery faces up before you remove it, then install the new battery the same way.
  • Test the fob on your car when ready after closing it to confirm the battery is seated correctly.
  • If the fob still does not work after a new battery, the problem is likely a worn button contact or water damage, not the battery itself.

Locate the seam and open the fob

Hold your fob in both hands and look for the thin line running around the edge where the front and back halves meet. On most Subaru fobs, this seam is visible as a slight ridge or shadow. The seam usually runs horizontally across the middle, though some models have it running vertically on the side.

Insert the edge of a coin (a penny or dime works well) or a small flathead screwdriver into the seam. Do not force it. explore steady, gentle pressure and twist the coin slightly, as if you were opening a paint can. The two halves will separate with a small click. If the fob resists, try a different spot along the seam—the seam may be tighter in some places than others.

Once the fob cracks open, use your fingernail or the coin to pry the halves apart the rest of the way. Be patient here. Plastic fobs crack easily if you yank them, and a cracked fob is harder to close tightly later. You should be able to separate the halves with your fingers once the initial seal breaks.

Remove the old battery and note its position

When you open the fob, you will see the battery sitting in a small metal or plastic holder. It looks like a shiny silver coin. Before you touch it, look at which side faces up. The battery has a flat side (the negative end) and a slightly domed side (the positive end). Most CR2032 batteries have a + symbol printed on the domed side. Photograph this with your phone if you are unsure, or straightforward remember: the domed side almost always faces up in Subaru fobs.

Use your fingernail or a coin edge to gently pry the old battery out of its holder. It should come free with light pressure. If it is stuck, do not force it—a stuck battery usually means corrosion or water damage inside the fob, which is a separate problem. Set the old battery aside.

Install the new battery and close the fob

Take your new CR2032 battery and place it in the holder with the domed side facing up (the same way the old one was facing). Press down gently until you hear or feel a small click. The battery should sit flush in the holder and not wiggle. If it feels loose, remove it and try again—the battery may be sitting at an angle.

Now close the fob by pressing the two halves together. Start at one end of the seam and work your way around, pressing firmly until you hear a click all the way around. The fob should feel solid and not have any gaps. If there is a gap, open it again and make sure the battery is seated all the way down in its holder, then try closing it once more.

Test the fob on your car

Walk to your car and press each button on the fob—lock, unlock, panic, trunk, or whatever buttons yours has. You should see the lights flash on your car and hear the locks respond. Press each button a few times to make sure they all work. If nothing happens, open the fob again and check that the battery is sitting flat in its holder with the domed side up. A battery that is tilted or upside down will not make contact.

If the fob still does not work after you have confirmed the battery is in correctly, the problem is not the battery. Subaru fobs can fail because the rubber button pads wear out, water gets inside and corrodes the circuit board, or the battery contacts become dirty. These are harder to fix at home and usually require a replacement fob or a trip to a Subaru dealer.

Where to buy a CR2032 battery

CR2032 batteries are sold everywhere. Check the pharmacy section of any grocery store, the battery aisle at a hardware store like Home Depot or Lowe's, or the electronics section of a drugstore like CVS or Walgreens. You can also order them online from Amazon or eBay. Buy a name brand like Energizer, Duracell, or Panasonic if you want the longest life—generic batteries work fine but may not last as long. A single battery costs $3 to $8 depending on the brand and where you buy it.

Some Subaru dealerships sell CR2032 batteries, but they usually charge more than a pharmacy or hardware store. If you are already at the dealership for service, ask the parts desk what they charge before you buy elsewhere. Many people buy a pack of two or four batteries at once so they have a spare on hand—a pack of four CR2032 batteries costs $10 to $15 and lasts for years if you store them in a cool, dry place.

Common mistakes to avoid

The most common mistake is installing the battery upside down. If the flat side faces up instead of the domed side, the battery will not make electrical contact and the fob will not work. If your fob does not work after you close it, open it again and flip the battery over before you assume it is broken.

The second mistake is not pressing the battery all the way down into its holder. If the battery is tilted or sitting too high, it will not touch the contacts. Press down firmly until you feel it settle into place. The third mistake is closing the fob too quickly before the battery is seated. Take a few seconds to make sure the battery is flat and centered before you snap the halves together.

Do not use a battery that is older than a few years or one that has been sitting in a hot car or a damp garage. Old batteries lose charge, and batteries exposed to heat or moisture may not work reliably. If you have an old CR2032 in a drawer, test it in another device first before putting it in your fob.

Frequently Asked Questions

What if my Subaru fob uses a different battery?

Most Subaru fobs use CR2032, but some older models use CR2025 or CR2016. Check your owner's manual or look at the battery holder inside the fob—it usually has the battery size printed on it. If you buy the wrong size, it will not fit or will not make contact. A pharmacy can tell you which battery your fob needs if you bring the fob in and ask.

Can I use a rechargeable battery in my key fob?

Rechargeable CR2032 batteries exist, but they are not recommended for key fobs. Rechargeable batteries have a lower voltage than disposable ones and may not work reliably in a fob. Stick with a standard disposable CR2032 battery. It is cheaper and more reliable.

How long does a CR2032 battery last in a Subaru fob?

A CR2032 battery usually lasts two to four years in a key fob, depending on how often you use it. If you press the buttons dozens of times a day, the battery will drain faster. If you use the fob only a few times a week, it may last longer. When the battery gets weak, the fob will work only at very close range or will stop responding to some buttons before others.

Why does my fob still not work after I put in a new battery?

If a new battery does not fix the fob, the problem is usually worn button contacts, water damage, or a broken circuit board. Water damage is common if the fob has been dropped in water or left in a humid environment. A worn button contact happens over time as the rubber pad degrades. Both of these require a replacement fob or professional repair, not a new battery.

Can I replace the battery in a Subaru fob that is water damaged?

You can open it and replace the battery, but if water has gotten inside, the circuit board may be corroded and the fob may not work even with a fresh battery. If the fob has been wet, let it dry completely in a warm, dry place for a few days before you try a new battery. If it still does not work, the fob itself needs to be replaced.