How to Replace a Subaru Key Fob Battery
If your Subaru's key fob has stopped locking or unlocking the doors reliably — or if you're getting a low battery warning on your dashboard — a dead or dying battery is almost always the cause. Replacing it is one of the simplest maintenance tasks a Subaru owner can do, typically taking under five minutes with no special tools.
Here's how the process generally works, what variables affect it, and what to watch for depending on your specific key.
How Subaru Key Fob Batteries Work
Subaru key fobs run on small, flat coin cell batteries — most commonly the CR2032 — though the exact battery type depends on the model year and key style. The fob sends a short-range radio signal to your car when you press a button. When the battery weakens, that signal becomes inconsistent: doors may not respond from a normal distance, or the fob may stop working entirely.
Most modern Subarus also display a "Key Battery Low" or similar warning message in the instrument cluster when the fob's battery is nearing the end of its life. Don't ignore that message — a completely dead key fob can leave you manually unlocking the door and unable to start the car if you don't know the workaround (more on that below).
What Type of Key Does Your Subaru Have?
Not all Subaru keys are the same, and the battery replacement process varies by key type.
| Key Type | Description | Battery Typically Used |
|---|---|---|
| Basic key fob | Separate fob with physical key | CR2032 (common) |
| Flip key fob | Key blade folds into fob body | CR1620 or CR2032 |
| Proximity/smart key | Keyless entry and push-button start | CR2032 (common) |
| Older remote fob | Pre-2010s style with larger body | Varies by generation |
Always verify the correct battery by checking the label inside your fob or your owner's manual — using the wrong size can damage the contacts or simply not fit.
General Steps to Replace the Battery
While specific steps vary by fob design, the process generally follows the same sequence:
1. Open the fob case. Most Subaru fobs have a seam around the edge. Insert a small flathead screwdriver (or a coin) into the notch or slot and gently pry the two halves apart. Some fobs require removing the physical key blade first — there's often a small release button on the side.
2. Locate and remove the old battery. The coin cell battery sits in a circular holder. Note which side faces up (positive side is usually marked). Use a fingernail or a small plastic pry tool to pop it out — avoid metal tools that could scratch the contacts.
3. Insert the new battery. Place the new CR2032 (or whatever your fob requires) in the same orientation as the old one. Press it firmly into the holder until it seats flat.
4. Reassemble and test. Snap the two halves back together. Test all buttons — lock, unlock, trunk release, and panic — from various distances.
🔋 What If the Fob Still Doesn't Work After a Battery Change?
A fresh battery doesn't always solve the problem. A few other possibilities:
- The fob may need to be re-synced to your vehicle. Some Subaru models lose their pairing after a battery swap or an extended dead period. The re-syncing process varies by model and year — your owner's manual usually walks through it.
- The fob may be damaged. If it's been dropped or submerged in water, internal components may be corroded or broken even with a good battery.
- You may have the wrong battery. Voltage and size both matter — a battery that physically fits but has a different voltage rating won't power the fob correctly.
Starting Your Subaru with a Dead Key Fob
If your proximity key fob battery dies completely and your Subaru has push-button start, most models are designed for this situation. Hold the fob directly against the start button while pressing it — the car reads a passive signal from the fob's transponder chip, which doesn't require battery power. This is a backup, not a long-term solution, but it can get you moving until you replace the battery.
Where to Buy the Replacement Battery
CR2032 batteries are available at grocery stores, pharmacies, auto parts stores, and online retailers. Prices are typically low — usually under a few dollars for a single cell, though multipack pricing varies. Avoid extremely cheap, off-brand cells — inconsistent quality can mean shorter life and unpredictable performance in electronics. Stick with recognized battery brands when possible.
What Shapes Individual Outcomes Here
Even for something as simple as a key fob battery, a few variables affect your experience:
- Model year and trim level determine which fob style your Subaru uses — and whether your car has a proximity system, a traditional remote, or both
- How long the battery has been dead affects whether re-syncing is needed
- Your specific fob's condition determines whether a battery is the only issue or one of several
- Regional availability of specific coin cell sizes can vary slightly, though CR2032 is widely stocked almost everywhere
The general steps apply across most Subaru models, but the exact battery spec, fob design, and any re-pairing steps depend on your specific vehicle's year and configuration — details your owner's manual will have, and that a dealership or locksmith can confirm if needed.
