Garmin Forerunner F31 Error Code Fix (Quick Guide)

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What This Error Means

F31 on a Garmin Forerunner means a firmware load failure.

The watch starts to boot, hits corrupt or incomplete software, and locks up on the F31 screen or reboots in a loop.

Buttons usually stop responding, it won't sync, and charging it doesn't clear the error by itself.

Official Fix

Garmin's playbook is simple: power-cycle it, fully charge it, then re-flash the firmware.

  • 1. Force a soft reset.
    Hold the Light/Power button for 15–20 seconds until the screen goes fully blank. Wait 10 seconds, then press and hold Light/Power again until the Garmin logo appears.
  • 2. Give it a solid charge.
    Clip it into the original charger. Plug into a known-good USB wall adapter, not a PC. Let it sit for at least 30–60 minutes, even if the screen looks dead at first.
  • 3. Try a normal boot.
    After charging, press Light/Power once and see if it gets past F31. If it boots, back up any data via the Garmin Connect app right away.
  • 4. Update the firmware the official way.
    Connect the watch to a computer with Garmin Express installed. Let Express detect the device and install any available software updates. Don't unplug or jiggle the cable during this.
  • 5. Run a factory reset from the menu (if it boots).
    On the watch: go to Settings > System > Reset and choose the full reset that wipes user data. This clears corrupted settings that can retrigger F31.
  • 6. If it's still stuck on F31, go to Garmin support.
    At this point Garmin usually treats it as a hardware/software failure that needs a service swap. They'll quote you a flat-fee repair or replacement based on the model and age.

The Technician's Trick

Here's what the bench techs do when the official dance doesn't cut it.

  • 1. Clean the power path first.
    Pop the watch out of the band if needed. Clean the metal charge contacts on the back of the watch and inside the clip with isopropyl alcohol or a pencil eraser. Any crud here can drop voltage just enough to crash firmware during boot.
  • 2. Force it into USB bootloader mode.
    This is the real reset. With the watch disconnected and powered off, hold the Back/Lap button. While holding it, clip on the USB cable and plug into a computer (not a charger). Keep holding 10–15 seconds until you feel a buzz or see a tiny USB/PC icon or storage device pop up on the computer.
  • 3. Let Garmin Express rebuild the software.
    Once the PC sees the watch, open Garmin Express. Remove the device from Express, then add it again so it treats it like new. If it offers to reinstall or repair the software, do it. Leave it alone until it finishes.
  • 4. If it mounts as a drive, clean the junk.
    If the watch shows up as a drive (GARMIN), delete only user stuff: activities, courses, custom watch faces, third‑party apps. Leave the system folders alone. Then rerun Garmin Express so it can push clean firmware and files.
  • 5. Hard power cycle if it's totally frozen.
    If none of the buttons respond, let the battery run flat completely. Leave it off the charger overnight. Next day, reconnect to a wall charger for at least an hour, then repeat the bootloader trick and Express reinstall.

If it still throws F31 after a clean firmware load and good power, the main board is usually done. No amount of button mashing will fix that.

Is It Worth Fixing? (The Financial Verdict)

  • ✅ Fix: Watch is under 4–5 years old, screen and buttons are fine, battery still lasts a full day+, and F31 showed up right after an update or random crash.
  • ⚠️ Debatable: Older Forerunner (5–7+ years), battery is weak, or you already have sticky buttons — compare Garmin's flat-fee swap price to the cost of a newer mid-range Forerunner.
  • ❌ Replace: Cracked screen, obvious water damage, swollen battery, or Garmin quotes a repair close to the price of a newer model — your money is better in a replacement watch.

Parts You Might Need

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See also

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