How To Replace Battery In Subaru Keyless Fob: Step-by-Step Guide
Replacing the battery in your Subaru keyless access smart fob or integrated ignition key takes less than five minutes and requires only a small flathead screwdriver and a fresh lithium coin cell. By understanding the specific mechanical release mechanism and the exact battery chemistry required for your fob model, you can prevent damage to the plastic housing and ensure proper transponder synchronization.
Pre-Operation & Equipment Checklist
Before beginning the battery replacement procedure, gathering the correct tools and understanding the structural design of your specific Subaru key fob is essential. Modern Subaru vehicles utilize several distinct key styles depending on the model year and trim level, ranging from traditional integrated flip keys to advanced push-button start smart fobs.
- Essential Gear, Tools, and Materials:
- One fresh CR2032 or CR1632 3-volt lithium coin cell battery (verify the exact size printed on your old battery before opening).
- A small, flathead precision screwdriver or a non-marring plastic trim removal tool.
- A clean, well-lit workspace free of moisture and static electricity.
- Mandatory Prerequisite Knowledge & Standards:
- Avoid touching the flat surfaces of the new lithium battery with bare fingers; natural skin oils can cause corrosion and discharge the cell prematurely. Handle the battery by its edges, ideally using clean gloves or non-conductive plastic tweezers.
- Note the orientation of the original battery (+ side facing up or down) to ensure the replacement is installed with the correct polarity.
- Estimated Budget & Duration Benchmarks:
- Total cost is typically between three and six dollars for a quality battery.
- Estimated completion time is three to five minutes.
Step-by-Step Subaru Key Fob Battery Replacement Workflow
Step 1: Extract the Mechanical Emergency Key
Locate the physical metal emergency key housed inside the electronic fob assembly. Press the physical release button, slide the locking switch located on the top or side of the fob housing, and pull the metal key straight out of the fob body.
Pro-Tip: Never force the metal key out without fully depressing the release latch, as this can snap the internal plastic retaining clip.
Step 2: Unlatch and Separate the Fob Housing Halves
Look inside the cavity left by the removed mechanical key to find a small, rectangular slot designed specifically to fit the tip of the emergency key or a small flathead screwdriver. Insert the tool gently into this slot and twist it like a door key. The plastic casing should pop apart along the seam, splitting the fob into two distinct halves.
Warning: Twist the tool gently. Excessive torque can crack the outer plastic shell or damage the rubber weather-sealing gasket inside.
Step 3: Remove the Circuit Board or Battery Tray
Carefully lift the internal electronic module or rubber protective cover out of the bottom shell. Depending on your specific Subaru key fob variant, the battery will either be exposed directly on the circuit board held down by a small metal clip, or it will be housed within a sliding plastic battery tray. If your fob uses a sliding tray, gently pull it out from the module.
Step 4: Extract the Depleted Battery and Install the New Cell
Note the polarity markings (positive "+" side usually facing upward) stamped onto the battery or housing. Gently slide or pop the old coin cell out of its retainer using your precision screwdriver, taking care not to bend the delicate metal contact prongs. Insert the new CR2032 or CR1632 lithium battery into position, ensuring it clicks securely under the retaining tabs with the positive side facing the correct direction.
Step 5: Reassemble and Test the Key Fob
Align the two plastic halves of the fob housing and press them firmly together with your fingers until you hear a series of snaps along the perimeter. Reinsert the metal emergency key until it clicks back into its locked position. Stand near your Subaru and test the functionality by pressing the lock, unlock, and trunk release buttons to confirm the LED indicator light flashes and the vehicle responds.
Subaru Forester Key Fob Battery
Subaru Key Fob Battery Specifications and Compatibility
| Subaru Key Fob Type | Model Years | Battery Size | Voltage | Common Tool Required |
|---|---|---|---|---|
| Push-Button Start Smart Fob (Square) | 2015 – Present | CR2032 | 3.0V | Flathead Screwdriver / Emergency Key |
| Push-Button Start Smart Fob (Oval) | 2013 – 2018 | CR2032 | 3.0V | Flathead Screwdriver |
| Integrated Key with Remote (Flip/Fixed) | 2010 – 2020 | CR1616 / CR2032 | 3.0V | Precision Screwdriver |
| Standard Keyless Entry Remote (FOB-4F) | 2008 – 2015 | CR2016 | 3.0V | Small Coin or Screwdriver |
Troubleshooting Common Subaru Key Fob Issues After Replacement
Even with a brand-new battery installed, users occasionally encounter operational glitches due to misalignment, static discharge, or vehicle-side synchronization loss. Review these frequent failure scenarios and their field fixes.
- Root Cause: The vehicle does not respond to remote commands despite installing a fresh battery.
- Actionable Fix: Verify that the battery was installed with the correct polarity (+ side facing the right direction). Remove the battery, clean the metal contact points with a cotton swab dipped in isopropyl alcohol to remove oil or residue, and reinstall it.
- Root Cause: The fob operates intermittently or only works when held directly against the push-button start ignition.
- Actionable Fix: You may have purchased a low-quality or expired coin cell battery. Test the voltage using a multimeter to ensure it outputs a minimum of 3.0 volts, or replace it with a fresh battery from a reputable brand (such as Panasonic, Energizer, or Duracell).
- Root Cause: The red LED indicator on the fob flashes when buttons are pressed, but the car doors do not lock.
- Actionable Fix: The key fob has lost synchronization with the vehicle's Body Control Module (BCM). Sit inside the vehicle with all doors closed, insert the key into the ignition (or follow your specific model's manual programming sequence), and cycle the ignition to resync the transponder codes.
Frequently Asked Questions
What size battery does a Subaru key fob take?
Most modern Subaru push-button start smart fobs use a standard CR2032 3-volt lithium coin cell battery. However, older integrated ignition keys and smaller remotes may require a CR1616 or CR2016 battery. Always check the physical markings on your old battery before purchasing a replacement.
Do I need to reprogram my Subaru key fob after changing the battery?
No, replacing the battery does not erase the internal transponder memory chip or unpair the fob from your vehicle. Your remote will remain paired to your Subaru's security system automatically once power is restored.
Why does my Subaru say "Keyless Access System Disabled" on the dash?
This warning message typically indicates that the key fob battery is critically low or completely dead, preventing the vehicle's antennas from detecting the smart fob inside the cabin. Replacing the coin cell battery immediately resolves this dashboard warning.
How do I open a Subaru smart fob without scratching the plastic?
To prevent cosmetic damage, wrap the tip of your flathead screwdriver in a small piece of electrical tape or use a dedicated non-marring nylon auto trim removal tool. Insert the tool carefully into the designated slot near the emergency key release and twist gently.
Keep your Subaru running smoothly by maintaining your keyless remotes with fresh batteries before complete power loss occurs. Explore our comprehensive DIY automotive maintenance guides for more tips on keeping your vehicle in peak operating condition.
