How To Change Battery Subaru Key: A Comprehensive DIY Guide

Replacing a Subaru key fob battery takes less than five minutes and requires only a small flathead screwdriver and the correct coin cell battery. Knowing the specific battery size for your particular fob type prevents remote malfunction and ensures seamless keyless entry functionality.

Pre-Operation & Equipment Checklist

Maintaining your Subaru keyless access remote or integrated ignition key ensures uninterrupted vehicle security and seamless entry. Over time, the internal lithium cell depletes, resulting in delayed lock responses, intermittent push-button start failures, or a dashboard warning indicating the access key is not detected.

• Essential gear, tools, and materials: A precision flathead jeweler screwdriver (1.6mm or 2.0mm), a clean microfiber cloth to prevent casing scratches, and a fresh lithium coin cell battery matching your specific remote type (typically CR2032 or CR1632).
• Mandatory prerequisite knowledge and standards: Work on a clean, well-lit, non-conductive surface. Avoid touching the flat faces of the new battery with bare fingers; skin oils can leave a residue that accelerates self-discharge and inhibits electrical conductivity. Handle the battery by its edges or use plastic tweezers.
• Estimated budget and duration benchmarks: Financial cost ranges from $3 to $8 for a name-brand battery replacement. The physical operation takes approximately 3 to 5 minutes from start to finish, requiring zero specialized diagnostic equipment or dealership programming.

Step-by-Step Subaru Key Fob Battery Replacement

Step 1: Extract the Mechanical Emergency Key

1. Locate the physical slide release button or release latch situated on the upper edge or side of the Subaru smart key fob housing.
2. Slide the mechanical release lever while simultaneously pulling firmly on the metal emergency key blade to slide it completely out of the fob body.
3. Set the extracted mechanical key aside in a secure location until the battery swap is fully completed.

Pro-Tip: If your Subaru key is an older standard integrated key-and-remote unit rather than a push-to-start smart fob, skip this emergency key extraction step and proceed directly to opening the outer plastic shell.

Step 2: Separate the Key Fob Casing Halves

1. Insert the tip of your flathead jeweler screwdriver into the exposed mechanical key slot or the designated pry notch located along the inner perimeter seam of the plastic housing.
2. Twist the screwdriver gently like a door key to pop the snap-fit plastic casing halves apart. Avoid forcing the plastic too aggressively to prevent snapping the internal alignment tabs.
3. Work the screwdriver tip incrementally around the perimeter until the front and rear shell components separate completely, exposing the internal electronic circuit board and battery compartment.

Warning: Exercise extreme care when separating the fob halves on newer Subaru proximity remotes to avoid damaging the integrated rubber weather-sealing gasket that protects the internal electronics from moisture.

Step 3: Remove the Depleted Battery and Install the Replacement

1. Carefully lift or tilt the internal circuit board or battery holder cover (depending on your specific fob model) to access the spent lithium coin cell.
2. Note the polarity orientation of the old battery before extraction—the positive (+) side with printed text and capacity specifications universally faces upward in all modern Subaru key designs.
3. Slide or lift the old battery out of its retaining clips, and insert the new CR2032 or CR1632 lithium cell at a slight angle, pressing it firmly downward until it clicks securely beneath the metal retention tabs.

Step 4: Reassemble and Test the Remote System

1. Align the front and rear plastic shell halves squarely over one another, ensuring the internal rubber gasket is seated properly in its track.
2. Apply firm, even thumb pressure around the entire perimeter of the casing until all snap-fit clips lock back into position with an audible click.
3. Reinsert the metal mechanical emergency key blade back into its housing slot until the retention latch engages securely.
4. Stand within range of your vehicle and test the lock, unlock, and panic functions to confirm immediate responsiveness.

Subaru Key Battery Specifications and Compatibility Matrix

Common Site Failures & Field Fixes

• Symptom: The key fob fails to unlock the vehicle doors immediately after installing a brand-new battery.
  
  
  • Root Cause: The replacement battery was handled with bare fingers, transferring oily residue that blocks electrical contact, or the battery was inserted upside down.
  • Actionable Fix: Disassemble the fob housing, remove the battery, clean both surfaces with a lint-free cloth dampened with isopropyl alcohol, and reinstall it with the positive (+) text-side facing upward.
• Symptom: The remote works only when held directly against the vehicle door handle or push-button start ignition switch.
  
  
  • Root Cause: Purchasing a cheap, expired, or low-quality off-brand coin cell battery that exhibits high internal resistance and sub-optimal voltage output.
  • Actionable Fix: Replace the budget cell with a fresh, name-brand lithium battery (such as Panasonic, Energizer, or Sony) purchased from a high-turnover retail supplier.
• Symptom: The plastic casing tabs break or the housing fails to snap tightly back together after battery installation.
  
  
  • Root Cause: Applying excessive leverage or twisting the screwdriver too deeply into the outer plastic seam during the initial opening phase.
  • Actionable Fix: Secure the misaligned casing edges using a tiny drop of clear electronic-safe silicone adhesive or order an inexpensive replacement aftermarket fob shell online and transfer the internal electronics module.

Frequently Asked Questions

What size battery does my Subaru key fob take?

Most modern Subaru push-button start smart fobs utilize a standard CR2032 3-volt lithium coin cell. Older integrated key-and-remote units typically require a slightly thinner CR1632 battery. Always check the physical stamp on your old battery or consult your owner manual to verify sizing before purchase.

Do I need to reprogram my Subaru key after changing the battery?

No, changing the battery in a Subaru key fob does not erase its internal programming or vehicle pairing memory. The transponder chip and remote frequency codes remain securely stored on the internal circuit board microchip during the brief power interruption of a battery swap.

Why is my Subaru dashboard still displaying a "Key Battery Low" warning?

If a fresh battery was just installed and the warning persists, the vehicle computer may require a drive cycle to re-synchronize with the updated key telemetry. Alternatively, ensure the new battery is fully seated under the metal clips and that the positive terminal is making clean, uninterrupted electrical contact.

Can I drive my Subaru if the key fob battery is completely dead?

Yes, you can still drive your vehicle even if the smart key battery is completely drained. For push-to-start models, hold the physical key fob directly against the engine start-stop button while pressing the brake pedal to allow the RFID emergency transponder coil to communicate with the ignition system.

Keep Your Subaru Operating Flawlessly Today

Mastering routine maintenance tasks like replacing your Subaru key fob battery ensures continuous security, reliable keyless entry, and zero unexpected roadside inconvenience. Order your replacement lithium coin cell battery today and complete this quick DIY procedure in minutes to restore peak remote performance.