What This Error Means

F31 on a Fitbit Charge 5 is a firmware failure code. The tracker tried to load or update its software and it bombed out, so it can’t start normally.

On the screen you usually see the F31 code, a stuck logo, or a blank screen that only wakes up when you put it on the charger. The guts are probably fine, but the software is confused or corrupted.

Official Fix

Fitbit’s official playbook is simple: power, restart, retry the update, then talk to support if it still screams F31. Do this in order:

  • 1. Give it a real charge
    • Use the original Charge 5 cable if you have it.
    • Plug into a steady USB wall adapter (not a laptop, hub, or car port).
    • Seat the tracker fully in the cradle. All pins must touch clean metal.
    • Let it sit at least 30 minutes, even if the screen looks dead.
  • 2. Hard restart the Charge 5
    • Keep it on the charger.
    • If your cable has a small button on the USB end, press that button 3 times, about 1 second between presses, then wait 10–15 seconds.
    • If there is no button, leave it on the charger and hold the side touch area for about 10 seconds until you feel a vibration or see the Fitbit logo.
    • If it reboots cleanly and the F31 screen is gone, you’re done. If F31 comes back, keep going.
  • 3. Clean up the phone side
    • On your phone, turn Bluetooth off, wait 10 seconds, then turn it back on.
    • Force close the Fitbit app, then reopen it.
    • Restart the phone if it’s been on for weeks without a reboot.
  • 4. Retry the firmware update from the Fitbit app
    • Open the Fitbit app, tap your profile picture, then tap your Charge 5.
    • If you see an Update banner, start it and set the phone down right next to the tracker.
    • Keep Wi‑Fi on, screen awake if possible, and don’t wander away with the phone until it finishes.
    • If the update completes, the F31 error should disappear.
  • 5. Remove and re-add the tracker
    • In the Fitbit app, remove the Charge 5 from your account.
    • On your phone’s Bluetooth settings, “Forget” the Charge 5.
    • Restart phone and tracker, then add the Charge 5 back in the Fitbit app and let it sync and update again.
  • 6. Try a different phone or tablet
    • Install the Fitbit app on another device you trust.
    • Log in with your same Fitbit account.
    • Pair the Charge 5 there and see if the update will push through without throwing F31.
  • 7. If F31 still won’t clear, go to Fitbit Support
    • At this point you’ve done the official steps a normal user can do.
    • Go to Fitbit Support via chat or email and tell them it’s stuck on F31 after restarts, re‑pairing, and trying a second phone.
    • They typically move to a warranty replacement or discount if the device is within its expected life and not damaged.

There is no official way for you to open the tracker or reflash the firmware yourself. It’s a sealed unit. If support can’t clear F31, they swap it; that’s the “authorized” fix.

Is It Worth Fixing? (The Financial Verdict)

  • ✅ Fix: Under warranty or just out of it, screen is fine, battery used to last more than 2–3 days, and F31 only started after an update. Your cost is time and maybe dealing with support, not parts.
  • ⚠️ Debatable: Tracker is 2–3 years old, battery life is already weak, and you have to fight with updates often. If support won’t replace it free, compare any paid “out of warranty” offer against the price of a newer model.
  • ❌ Replace: Screen is cracked, band lugs are damaged, battery dies in under a day, or the body has water/impact damage on top of F31. Don’t sink hours into it; put that money toward a fresh tracker.

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