Replace Battery Subaru Key Fob

Why Replacing a Subaru Key Fob Battery Matters

Replace Battery Subaru Key Fob: Your key fob is the lifeline to your Subaru: locking/unlocking doors, possibly arming/disarming security systems, and in push-button start models, enabling ignition functionality. Over time, the battery inside the key fob drains. When that happens, you may experience symptoms like:

• Fob working only at very short range or inconsistently

• “Battery Low” warning message on dash (some Subarus)

• Fob completely not responding at all

When the battery is dead, you could be locked out of remote conveniences, or even face difficulty starting your vehicle in certain setups. The good news: for many Subaru models, replacing the fob battery is a do-it-yourself task that’s quick, inexpensive, and doesn’t require advanced tools — so long as you follow proper steps and take necessary precautions.

However, some newer Subaru key fobs may require reprogramming or dealer intervention after opening, depending on how the fob is built.

In this article you will learn:

1. The types of Subaru key fob batteries (which battery your fob likely uses)
2. Tools and safety tips needed
3. Step-by-step instructions by fob style
4. How to reprogram or reset the fob (if needed)
5. Troubleshooting common problems
6. Best practices and when to seek professional help

Let’s begin.

Types of Subaru Key Fob Batteries & Which to Buy

Before opening your fob, it’s important to know which battery to purchase. Subaru has used several coin (button cell) batteries depending on the age, model, and design of the key fob.

Here are the most common battery types used in Subaru key fobs:

Important tips when selecting the battery:

• Always check the imprint on the current battery (if visible) before buying a new one.
• Use good brand name coin batteries (e.g., Panasonic, Sony, Duracell) — substandard ones may lose connectivity.
• Be careful handling new battery — touch it as little as possible, especially the contact surfaces, to avoid oils/contaminants.

Once you have the correct battery, you’ll need basic tools and a careful approach.

Tools, Safety Tips & Preparations

Before attempting battery replacement, prepare properly so you don’t damage the fob or lose small parts.

🧰 Tools & Materials You’ll Need

• Small flathead screwdriver, or a plastic pry tool
• A fresh coin battery of the correct type (CR2032, CR2025, or CR1620)
• A soft cloth or lint-free towel to rest the fob on
• Optionally, gloves or finger cots to avoid fingerprint oils on battery surfaces
• (If reprogramming later) knowledge of your fob’s serial / code digits

✅ Precautionary Safety Tips

1. Work in a clean, well-lit area so you don’t lose tiny components or screws.
2. Use a soft cloth under the fob to prevent scratches.
3. Be gentle when prying; plastic casings can crack if forced.
4. Note orientation of the battery before removal (which side is facing up).
5. Avoid touching the battery contacts and contact surfaces with fingers.
6. Keep small screws or parts in a safe place (tray, magnetic bowl).
7. For fobs that require reprogramming, record any needed serial / code before opening.

With tools and precautions ready, we can dive into the actual replacement process — which varies by fob type.

How to Replace the Battery: Step-by-Step by Fob Style

Below are detailed instructions for the most common Subaru key fob types: modern, older teardrop, and exposed metal key fobs.

1. Modern Bulging Rectangle Fob (CR2032 battery)

This is common in newer Subaru models.

Steps:

1. On the back of the fob, press the small silver tab to release and remove the metal emergency key (key shank).
2. Where the metal key was, you’ll see a gap / seam between the two halves of the plastic shell. Insert the tip of the key or a flathead screwdriver into that gap.
3. Gently twist or pry to pop open the fob housing — don’t force it.
4. Inside, locate the flat, round battery. It may be on one side of the circuit board.
5. Release the battery from its retaining tabs — gently pry it out, noting which side (polarity) faces upward.
6. Insert the new CR2032 battery, ensuring the same orientation (usually the “+” side is up).
7. Snap the two halves of the fob back together, ensuring all clips are aligned.
8. Reinsert the metal key back into its slot.

At this point, test the fob to see if it works. In many cases, no reprogramming is required.

2. Teardrop-Style Fob (CR2025 battery)

Older Subaru models sometimes used a teardrop-shaped fob.

Steps:

1. Find the small indentation or notch along the seam between the front and back halves of the fob.
2. Insert a small flathead screwdriver or pry tool into that notch and gently twist to separate the two halves.
3. Once open, you’ll see the old battery held by tabs. Pry it out carefully, remembering orientation.
4. Insert the new CR2025 battery in the same direction.
5. Snap the fob halves back together.

In many cases, no additional programming is needed for teardrop models.

3. Exposed Key with Buttons (CR1620 battery)

Some older Subarus use a fob where the metal key is always exposed, with a button panel. These often have a nested inner casing.

Steps:

1. Identify a small seam / indentation between the two halves of the outer casing. Insert a flathead screwdriver and twist to open it.
2. Remove the inner module from the outer shell.
3. The inner module has a smaller casing held by tabs — press these tabs to open it.
4. Inside, you’ll find the CR1620 battery. Pry it out gently, noting orientation.
5. Place the new battery in the same way.
6. Reassemble the inner module, place it back into the shell, and snap everything closed.

Because this fob is older, it’s less likely to require reprogramming — but always test the functionality.

Reprogramming or Resetting the Fob (If Needed)

In many Subaru models, once the battery is replaced, the key fob will resume working without extra steps. However, some newer models (especially with more advanced security or smart key systems) may lose synchronization and need to be reprogrammed by a dealer.

If your fob doesn’t function after replacement, here’s what to try (for models where manual programming is possible) and what to expect:

🔄 Manual Reprogramming (for older / simpler models)

Some Subaru fobs allow programming via a sequence in the vehicle:

1. Record the serial / code number printed inside the fob before opening.
2. Sit in the driver’s seat with all doors closed, engine off.
3. Open driver’s side door; press the unlock button on car’s door.
4. Turn the key to accessory position, then back to off repeatedly (often 10 times) fairly quickly. — you may hear a chime.
5. Open and close the driver’s door (you may hear another chime).
6. Within a set time (e.g. 45 seconds), enter the serial number digits via pressing lock/unlock on the doors (e.g. lock = increment, unlock = move to next number).
7. If successful, you’ll hear a final chime or see locks cycle.
8. Test the fob.

Note: This method works only on certain older Subaru models. Many modern fobs with encrypted codes cannot be self-programmed and must be handled by a Subaru dealer or qualified locksmith with equipment.

🏢 When Dealer or Professional Help Is Required

• If your fob uses advanced encryption or “smart key / push start” systems, the dealer may need to reprogram or re-pair the fob.
• Some fobs are locked until opened at a service center.
• If your fob fails after battery replacement and manual techniques don’t bring it back, professional diagnostics may uncover issues with circuits or contacts.

If ever in doubt, consult a Subaru service center or experienced auto locksmith.

Troubleshooting & Common Issues After Replacement

Even after replacing the battery, you might run into hiccups. Below are common problems and tips to solve them.

❌ Fob still doesn’t work

• Check the battery orientation — if reversed, no connection.
• Ensure the battery is firmly seated and the contacts touch.
• Make sure no dust or oxidation is interfering.
• Confirm the battery is fresh and at full voltage.
• In some cases, internal components (buttons, circuit board, contacts) may be damaged.

⚠️ Weak range or intermittent operation

• The battery may be weak or borderline — try another new battery.
• Contacts or battery holders may be bent or loose.
• The antenna or transmitter portion inside fob may be partially bent or misaligned.
• Environmental interference (large metallic objects, signal jammers) can reduce effective range.

🔐 Reprogramming failed or fob not recognized

• The fob’s memory could have been erased or corrupted.
• The fob may be locked to a different vehicle (if secondhand).
• You may have missed a timing window in the reprogramming steps.
• Some fobs absolutely require dealer-level tools to reprogram.

🧩 Physical damage or cracks

• Cracked housing may cause poor fit or contacts losing tension.
• Over-prying or forcing the case can permanently damage it.

If the problem persists despite trying the usual fixes, it may be wise to replace the entire key fob or seek a professional repair.

Best Practices, Tips & When to Seek Help

To make your battery replacement safer and more effective, follow these best practices:

• Always use a good quality battery — “cheap” ones may fail prematurely or misfit.
• Label or photograph the battery orientation before removal.
• Work slowly, gently, and don’t force plastic snaps.
• After replacement, immediately test all functions (lock/unlock, trunk, panic) before reassembly.
• Consider replacing the battery proactively every 3–5 years, even if fob still working, to avoid sudden failure.
• Keep the emergency metal key handy in case fob fails entirely.
• If your fob definitely requires reprogramming or specialized tools, contact a Subaru dealer or a trusted auto locksmith who can handle obsolete or encrypted fobs.

Finally, if you’re uncomfortable opening the fob or if it’s a high-end model with push-to-start and smart encryption, you may choose to let a professional do the work — especially if the warranty or fob damage risk is high.

Conclusion

Replacing a Subaru key fob battery is, for many models, a quick and straightforward DIY job — saving time and money. The key steps are:

1. Identify which battery your fob uses (CR2032, CR2025, or CR1620)
2. Use gentle tools and care to open the fob housing
3. Remove the old battery and install a fresh one with proper orientation
4. Snap the fob back together and test
5. If needed, reprogram or reset the fob (if your model allows)
6. Troubleshoot issues like weak range or non-functioning fob

However, because Subaru has evolved its key fob systems over time, some newer fobs may require dealer-level programming or advanced equipment. Always refer to your vehicle’s owner manual for model-specific instructions and any warnings.

If you tell me your Subaru’s year and model (e.g. “2017 Subaru Forester”), I can send you a tailored step-by-step guide (with images) matching your exact fob type.

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