How to Change the Battery in a Subaru Key Fob
A dead key fob battery is one of those minor inconveniences that catches most drivers off guard — usually in a parking lot, usually at the worst time. The good news is that replacing the battery in a Subaru key fob is a straightforward DIY task that takes a few minutes and costs very little. Understanding how it works, which battery you need, and what to watch for afterward makes the process much smoother.
How Subaru Key Fobs Work
Subaru key fobs transmit a short-range radio signal to your vehicle. When you press a button — lock, unlock, panic, or remote start — the fob sends an encrypted code that your car's receiver recognizes. That signal requires a small, flat coin cell battery to power the transmitter circuit inside.
Most Subaru fobs use very little power in standby, but over time — typically one to three years depending on usage — the battery voltage drops below the threshold needed for reliable transmission. You'll usually notice the range getting shorter before the fob stops working entirely.
Which Battery Does a Subaru Key Fob Use?
The battery type depends on your specific fob model, which varies by generation and trim level. The two most common batteries across Subaru's lineup are:
| Battery Type | Common Subaru Models/Years |
|---|---|
| CR2032 | Many Outback, Forester, Impreza, Legacy, Crosstrek models (various years) |
| CR2025 | Some older Subaru fobs and select trim configurations |
The CR2032 is slightly thicker than the CR2025 but both are 20mm in diameter. Do not substitute one for the other without confirming your fob's requirement — forcing the wrong battery can damage the housing or cause a poor connection.
The definitive source is your owner's manual, which lists the correct replacement battery. You can also check the battery already inside your fob once you open it.
What You'll Need
- A small flathead screwdriver or a thin coin
- The correct replacement battery (CR2032 or CR2025)
- Optionally, a small piece of tape or cloth to protect the fob housing from scratches
Batteries are available at pharmacies, hardware stores, electronics retailers, and online. Expect to pay $1–$5 per battery, though prices vary by brand and where you shop.
Step-by-Step: Changing the Battery 🔋
Step 1 — Find the Seam or Release
Most Subaru fobs have a small notch or seam along the edge where the two halves of the housing meet. Some models also have a hidden mechanical key inside — you may need to slide a release button and pull out the emergency key first to access the battery compartment.
Step 2 — Open the Fob
Insert a small flathead screwdriver or coin into the seam. Twist gently to pry the two halves apart. Avoid using excessive force — the plastic clips are small and can break if you apply too much pressure at one point. Work around the seam gradually if it's tight.
Step 3 — Note the Battery Orientation
Before removing the old battery, observe which side is facing up — typically the positive (+) side faces up, but confirm this on your specific fob. Getting the orientation wrong will prevent the fob from working.
Step 4 — Remove and Replace the Battery
Use your fingernail or the screwdriver tip to gently lift the old battery out of its holder. Insert the new battery in the same orientation. You should feel or hear a subtle click or snap as it seats properly.
Step 5 — Reassemble and Test
Snap the two halves of the fob back together firmly. Press each button to verify the fob is working. Test it at your normal operating distance from the vehicle.
When the Fob Still Doesn't Work After a Battery Change
If your fob isn't responding after a fresh battery, a few things could be happening:
- Incorrect battery orientation — flip it and try again
- Battery contact corrosion — inspect the metal contacts inside the fob for any white or greenish residue; this can be gently cleaned with a dry cotton swab
- Wrong battery type — double-check that you used the correct part number
- Fob synchronization — some Subaru models require you to resync the fob to the vehicle after a battery replacement. This process typically involves sitting in the driver's seat, closing the door, and following a specific button sequence outlined in the owner's manual. The steps vary by model year.
- Damaged fob — physical damage from drops or water exposure can affect the circuit board, which a battery swap won't fix
Smart Key and Proximity Fob Variations ⚙️
Newer Subaru models with keyless access (proximity entry or push-button start) use fobs with slightly different designs, but the battery replacement process is similar. These fobs may also contain a backup mechanical key blade. If your vehicle has push-button start and the fob battery is dead, most Subaru models allow you to hold the fob directly against the start button to initiate startup — the car can draw enough signal to recognize the fob even with a very low battery.
The Part That Varies
The specific battery size, fob design, and any required resync procedure all depend on your model year and trim level. A 2015 Forester fob and a 2023 Outback fob are not identical in construction. What's consistent across Subaru models is the general approach — but the exact steps, battery spec, and whether a resync is needed are details that only your owner's manual or a Subaru service technician can confirm for your specific vehicle.