How To Change Subaru Key Fob Battery: A Complete Step-by-Step Guide
Replacing a Subaru key fob battery is a straightforward five-minute maintenance task requiring only a flathead screwdriver and a fresh CR2032 or CR1632 lithium coin cell. By understanding your specific fob configuration—whether standard integrated ignition key or modern push-to-start smart fob—you can safely swap the power source without damaging the delicate internal circuit board or breaking the weather-sealed plastic housing.
Pre-Operation & Equipment Checklist
Proper preparation ensures a seamless battery replacement without damaging the delicate plastic clips or rubber gaskets inside your Subaru key fob. Whether you drive an Outback, Forester, Crosstrek, or WRX, the internal electronics require clean handling to prevent premature discharge or signal interference.
- Essential Equipment and Materials:
- Replacement lithium coin cell battery (CR2032 for most modern smart fobs; CR1632 for older integrated metal-key fobs). Always verify the exact stamp on your old battery before installing.
- Precision flathead micro-screwdriver or a plastic trim removal spudger.
- Clean, lint-free microfiber cloth to wipe oils from the new battery surface.
- Mandatory Prerequisite Knowledge:
- Avoid touching the flat sides of the new lithium battery with bare fingers; natural skin oils can leave a corrosive residue and cause micro-shorting, drastically reducing battery life span. Use non-conductive tweezers or clean gloves if possible.
- Understand that your vehicle's security transponder chip remains safely seated inside the housing and will not require reprogramming simply due to a dead battery swap.
- Project Benchmarks:
- Estimated duration: 3 to 5 minutes per fob.
- Estimated cost: Three to five dollars for a quality brand-name lithium cell battery.
Step-by-Step Key Fob Disassembly and Battery Replacement
Step 1: Extract the Mechanical Emergency Key (Smart Fobs Only)
If your Subaru features a push-to-start ignition system, locate the silver sliding release button or latch on the top or side of the key fob housing. Slide this release mechanism firmly while simultaneously pulling the metal emergency key blade outward away from the plastic body until it slides completely free. Setting this mechanical key aside exposes the primary seam of the outer plastic shell.
Warning: Never force the emergency key out without fully engaging the release slider, as this can snap the internal plastic retaining clip and ruin the fob housing.
Step 2: Pry Open the Outer Housing Shell
Insert the tip of your flathead screwdriver or plastic pry tool into the designated slot near the emergency key channel or along the side seam of the fob. Gently twist the tool to pop the two halves of the plastic casing apart. Work your way slowly around the perimeter of the fob, applying light, even leverage until the snaps release and the case separates into a front and back half.
Step 3: Remove the Circuit Board and Old Battery
Lift the rubber keypad membrane or carefully extract the internal electronic circuit board module from the housing if it does not remain seated in one half of the shell. Locate the battery retention compartment on the reverse side of the circuit board. Gently push the old coin cell battery out of its retaining clip or lift it out using your micro-screwdriver, taking care not to bend the metal contact prongs.
Pro-Tip: Note the orientation of the old battery before removal; the positive face—marked with the battery model number and a plus symbol—must point upward in the exact same direction when the new cell is installed.
Step 4: Install the Fresh Lithium Cell and Reassemble
Slide or press the new lithium coin cell battery firmly into the metal retaining bracket until it clicks securely into place. Re-align the circuit board inside the front half of the plastic housing, ensuring the rubber seal is seated flat to protect against moisture ingress. Snap the two housing halves back together by applying firm, uniform pressure around the edges until every plastic clip engages with an audible click. Re-insert the mechanical emergency key back into its slot until it locks securely.
Subaru Forester Key Fob Battery
Subaru Key Fob Battery Specifications and Compatibility Matrix
| Subaru Model Year Range | Fob Type | Required Battery Size | Nominal Voltage |
|---|---|---|---|
| 2015–2024 Models | Push-to-Start Smart Fob | CR2032 | 3.0V |
| 2010–2018 Models | Integrated Ignition Key Fob | CR1632 | 3.0V |
| 2005–2012 Models | Standard Key with Separate Fob | CR2016 | 3.0V |
| 2019–2024 Models | Ascent / Outback Keyless Remote | CR2032 | 3.0V |
Common Site Failures and Field Fixes
- Root Cause: The key fob still fails to unlock doors or start the engine after installing a brand-new battery.
- Actionable Fix: Inspect the battery orientation to ensure the positive side is facing upward. Additionally, wipe the battery clean with a dry microfiber cloth to remove any fingerprint oils that might be disrupting electrical contact.
- Root Cause: The plastic housing snaps do not align or close flush after reassembly.
- Actionable Fix: Check that the internal rubber gasket and circuit board are sitting completely flat inside their alignment pins. Forcing a misaligned case will crack the plastic housing.
- Root Cause: The vehicle displays a "Key Not Detected" warning even with a fresh battery installed.
- Actionable Fix: Hold the Subaru key fob directly against the push-to-start ignition button while pressing the brake and the start button to allow the near-field communication (NFC) chip to register.
Frequently Asked Questions
Do I need to reprogram my Subaru key fob after changing the battery?
No, replacing the physical coin cell battery does not erase or disrupt the programmed transponder memory chip inside the fob. Your vehicle will recognize the key immediately once the new power source is installed.
What battery size does a modern Subaru push-to-start fob require?
The vast majority of modern push-to-start Subaru fobs from 2015 onward utilize a standard 3-volt CR2032 lithium coin cell battery. Always verify by checking the stamp on your old removed battery.
Why is my key fob range still poor after installing a new battery?
Poor range can be caused by using a low-quality or expired generic battery brand. Switch to a reputable manufacturer like Panasonic, Energizer, or Duracell, and ensure the interior contacts are free of corrosion.
How do I open my Subaru door if the key fob battery dies completely?
Use the mechanical emergency key hidden inside your smart fob. Slide the release latch on the fob, pull the metal key out, and insert it into the physical key cylinder located discreetly underneath a small plastic cover on the driver-side door handle.
Can I drive my Subaru if the key fob battery is completely dead?
Yes, you can still start your vehicle by holding the dead fob directly against the start button while pressing the brake pedal, utilizing the backup immobilizer induction loop in the steering column or ignition switch.
Keep your Subaru operating at peak reliability by stocking up on the correct replacement batteries and addressing low-voltage warnings before total power loss occurs.
