The battery in your Subaru key fob lasts three to four years, then dies like any other battery

When your Subaru key fob stops locking or unlocking the car, the battery is almost always the culprit. The fob uses a coin-cell battery—usually a CR2032 or CR2025—that you can buy at any drugstore for a few dollars and swap out yourself in under a minute. You do not need to go to the dealer or call a technician.

The whole job is: pop open the fob case, note which side the battery sits on, slide the old battery out, slide the new one in the same way, and close the case. If your fob has two buttons, the process is identical. If it has four buttons, you may need to remove a small circuit board first, but it still takes less than five minutes.

Key Takeaways

  • Subaru key fobs use a CR2032 or CR2025 coin-cell battery that you can buy at a pharmacy, grocery store, or hardware store for two to five dollars.
  • The fob case opens by sliding a small metal or plastic tab, or by gently prying the two halves apart with a flathead screwdriver.
  • The battery slides in with the positive side (marked with a +) facing up or toward the circuit board, depending on your fob model.
  • After you install the new battery, test the lock and unlock buttons before you put the fob back in your pocket.

Identify which battery your fob needs

Before you buy a battery, you need to know which type your fob uses. The easiest way is to open the fob and look at the old battery itself—the size and model number are printed on it. If the fob is completely dead and you cannot open it, check your Subaru owner's manual, which lists the battery type for your model year.

Most Subaru fobs from 2000 onward use a CR2032 battery. Some older models and a few newer ones use a CR2025. The two are nearly identical in size, but they have different thicknesses. If you buy the wrong one, it will still fit in the case, but it may not make reliable contact with the terminals. When you buy the battery, buy two—one to install now and one as a spare.

Open the key fob case

Subaru fobs open in one of two ways. The first and most common is a sliding tab on the side or back of the case. Look for a small metal or plastic ridge that runs perpendicular to the fob's length. Push or slide that tab in the direction the arrow points (if there is one), and the case will separate into two halves. The battery sits in one half; the circuit board sits in the other.

If your fob has no visible tab, use a flathead screwdriver or a coin to gently pry the two halves apart. Start at a corner and work your way around the edge. The case is plastic and will separate without much force—if you have to push hard, you are probably prying in the wrong spot. Once the case is open, set the circuit board aside on a clean surface so you do not lose any small springs or contacts.

Remove the old battery and install the new one

The battery sits in a small metal or plastic holder with two contact points. On most Subaru fobs, the battery slides out toward the edge of the case. Push gently on the battery itself or on the holder, and it will slide free. If the holder has a small spring underneath, be careful not to lose it—set it aside on the table in front of you.

Before you install the new battery, look at which way the old one was facing. The positive side (marked with a +) should face up or toward the circuit board. Slide the new battery into the holder the same way the old one came out, with the positive side in the same direction. Push gently until it sits flat and makes contact with both terminals. If the holder has a spring, make sure the spring is underneath the battery before you close the case.

Close the case and test the fob

Align the two halves of the case so the edges line up evenly. If your fob has a sliding tab, slide it back into place until you hear or feel a click. If you pried it open, press the halves together firmly until they snap shut. The case should be tight enough that you cannot easily pull it apart by hand.

Before you put the fob back in your pocket, test both the lock and unlock buttons. Stand near your car and press each button to make sure the lights flash and the locks respond. If nothing happens, open the case 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 does not work, the circuit board may be damaged, and you will need to contact a Subaru dealer for a replacement fob.

Where to buy a replacement battery

CR2032 and CR2025 batteries are sold everywhere. You can find them at any pharmacy (CVS, Walgreens), grocery store, hardware store (Home Depot, Lowe's), or big-box retailer (Target, Walmart). They usually cost between two and five dollars per battery. Some stores sell them in multipacks of four or more, which is worth buying if you have multiple fobs or want spares on hand.

You can also order them online from Amazon or the manufacturer's website, but that takes several days. Since the battery is inexpensive and widely available, buying it in person is usually faster and lets you test the fob the same day.

What to do if the fob still does not work

If you installed a new battery and the fob still does not lock or unlock the car, the problem is not the battery. The circuit board may have water damage, a broken button contact, or a failed component. You can try cleaning the inside of the case and the circuit board with a dry cotton swab to remove any dust or corrosion, but if that does not help, the fob needs to be replaced.

Contact a Subaru dealer or a local locksmith who programs car keys. They can order a new fob and program it to your car. The cost varies by model year and dealer, but expect to pay between 150 and 400 dollars for a new fob with programming. Some dealers offer refurbished fobs at a lower price. If you have a spare fob, you can use that while the new one is being made.

Frequently Asked Questions

Can I use a different battery size if I cannot find a CR2032?

No. A CR2025 is thinner and may not make reliable contact. A CR2016 is too small. Always use the exact battery type your fob is designed for. If your local store is out of stock, order online or try another store nearby.

What if I drop the battery or the spring while the case is open?

The spring is small but important—it holds the battery against the contact points. If you lose it, the battery will not make electrical contact and the fob will not work. If this happens, contact a Subaru dealer or a locksmith and ask them to install the battery for you.

How long does a new battery last?

A new CR2032 or CR2025 battery typically lasts three to four years in a Subaru key fob, depending on how often you use the fob. If you use the fob multiple times per day, the battery may last only two to three years.

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

No. The fob does not need to be reprogrammed. Once the new battery is installed and making contact, the fob will work when ready. If it does not work right away, the battery is not seated correctly or the fob has a hardware problem.

Can I replace the battery in a keyless entry fob that is not a traditional key fob?

Yes, if it is a small handheld remote. The process is the same. If you have a push-button start fob or a fob built into a flip key, the battery replacement may be more complex. Check your owner's manual or contact a dealer for those models.