Fitbit Charge 5 F40 Fix: Straight-To-The-Point Guide

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What This Error Means

F40 on a Fitbit Charge 5 means the tracker hit a system fault, usually when trying to start an exercise, GPS, or sensor-heavy feature.

In plain terms: the tracker tries to fire up a feature, the internal check fails, it crashes, and you get an F40 error instead of your workout starting.

Official Fix

Fitbit’s official playbook is: restart, recharge, update, reset, then replace if it still acts up.

  • 1. Do a basic restart on the Charge 5
    • Wake the screen, swipe down to find Settings.
    • Scroll to Restart Device (or similar), tap it, confirm.
    • Let it shut down and boot back up, then try starting the same workout again.
  • 2. Give it a solid charge
    • Clip it firmly into the original charging cable. Make sure the pins line up and it actually shows charging.
    • Use a wall USB adapter, not a weak laptop port or TV.
    • Leave it for at least 2 hours, then retry the activity that was throwing F40.
  • 3. Check for a firmware update in the Fitbit app
    • On your phone, open the Fitbit app.
    • Go to the Today tab > tap your profile icon > tap your Charge 5.
    • If you see an Update banner, run the update with the band on the charger, phone nearby, Wi‑Fi on.
    • When it finishes, restart the band again and test for F40.
  • 4. Factory reset (Clear User Data) – Fitbit’s official nuclear option
    • Warning: this wipes unsynced data and resets settings. Sync once first if you can.
    • On the Charge 5, go to Settings > Device Info > Clear User Data (wording may be slightly different).
    • Confirm the reset and wait for it to reboot to the setup screen.
    • In the Fitbit app, set it up again as a new device and test if F40 still appears.
  • 5. Still getting F40? Official line: contact Fitbit Support
    • If restart, update, and full reset don’t kill F40, Fitbit treats it as a likely hardware fault.
    • Go through the Fitbit app or Fitbit’s support site and start a warranty/repair/replacement request.
    • Tell them the exact model (Charge 5) and the error code F40 and what you’ve already tried. They usually swap the device if it’s in warranty and the code is persistent.

The Technician’s Trick

When the regular reset routine doesn’t cut it, here’s what people who see these all the time actually do.

  • 1. Full app + Bluetooth purge before setup
    • Sync once if it will let you, just to save whatever data you can.
    • In the Fitbit app, go to your profile > tap the Charge 5 > scroll down and tap Remove This Device.
    • On your phone, open Bluetooth settings, find the Charge 5 entry, and tap Forget / Remove.
    • Now, on the tracker, run Clear User Data again from Settings > Device Info.
    • Restart your phone. Then open the Fitbit app and add the Charge 5 back like it’s brand new.
    • This forces a clean pairing and a fresh config. It often kills stubborn F40 errors that survive a simple reset.
  • 2. Bypass the failing bit (GPS/sensors) so you can still use the band
    • If F40 only pops when you start outdoor runs/walks, the GPS or sensor load is probably what’s crashing it.
    • On the Charge 5, open the Exercise app, pick the activity you use (Run, Walk, Bike), then hit the settings/gear icon if it shows.
    • If there’s a GPS setting, switch it from built‑in to Phone GPS or Off. That stops the band from leaning on its own GPS chip.
    • In Settings, you can also turn off extras like Always-On Display and limit background sensors. Less load, fewer crashes.
    • Result: you may lose onboard GPS tracks, but you usually stop seeing F40 and can still track basic workouts and daily stats.

Is It Worth Fixing? (The Financial Verdict)

  • ✅ Fix: Under ~2 years old, still under warranty, F40 only shows up sometimes and improves after reset/update.
  • ⚠️ Debatable: Out of warranty, battery already fading, but you just need basic tracking and the GPS-bypass trick makes it usable.
  • ❌ Replace: 3+ years old, weak battery or cracked screen, F40 comes back even after full reset and clean setup – don’t sink money into it, put it toward a new tracker.

Parts You Might Need

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See also

Dealing with other stubborn error codes around the house? These breakdown guides might help: