Fitbit Charge 5 F25 Error Code Guide (Fast Fix)

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What This Error Means

On a Fitbit Charge 5, code F25 is an ECG reading fault. The ECG app can’t lock onto a clean electrical signal from your heart, so it cancels the test.

Nothing is physically jammed inside the watch — the sensors just aren’t getting a strong enough, stable signal through your skin.

Official Fix

Fitbit’s playbook is simple. Make the signal cleaner and reset the basics:

  • Wear it in the right spot
    Wear the Charge 5 1–3 finger widths above the wrist bone. Strap snug, no daylight between the back of the watch and your skin.
  • Clean the contact points
    Wipe the back of the device and the two side ECG panels with a soft, slightly damp cloth.
    Dry everything completely so there’s no lotion, sweat, or soap film.
  • Set yourself up properly
    Sit down, relax for a minute, and rest both forearms on a table with palms up.
    Open the ECG app on the Charge 5. Keep your phone nearby with Bluetooth on and Fitbit app running.
  • Hold it exactly how Fitbit wants
    With the opposite hand, lightly pinch the sides of the Charge 5 using thumb and index finger.
    Don’t squeeze hard, don’t move, don’t talk, and don’t tap the screen during the 30‑second reading.
  • Kill obvious interference
    Remove metal bracelets, other watches, and big rings on the same hand.
    Avoid resting your arms on a metal desk or laptop chassis while recording.
  • Update the software
    In the Fitbit app, sync the device and install any pending firmware update.
    Make sure the Fitbit app itself is updated from the App Store / Play Store.
  • Reboot everything
    On the Charge 5: Settings > Device Info > Reboot Device.
    On the phone: toggle Bluetooth off and on, or just restart the phone, then open Fitbit and sync again.
  • Last resort: factory reset, then test
    On the Charge 5: Settings > Device Info > Clear User Data (this wipes the device).
    Set it up again in the Fitbit app as a new device, enable ECG, then try another reading.
    If F25 pops every single time even after this, Fitbit’s official answer is: contact support for a warranty check or replacement.

The Technician’s Trick

When you follow the script and F25 still won’t die, this is the real‑world stuff techs use:

  • Flip it to the inside of the wrist
    Rotate the Charge 5 so it sits on the inner wrist or a bit up the forearm where there’s more flesh.
    Thicker tissue often gives a stronger ECG signal than the bony top of the wrist.
  • Warm and hydrate the skin
    Cold, dry skin is terrible for ECG. Wear the watch for 10–15 minutes first, or rub the area until it feels warm.
    If your skin is very dry, put on a tiny amount of lotion 5–10 minutes before the test, then wipe off any excess so it’s just slightly moisturised, not greasy.
  • Use a basic silicone band
    Loose metal or woven bands can mess with contact. Swap to a plain, snug silicone band for ECG tests and tighten it one notch.
  • Cut the RF noise
    Try a reading with the Charge 5 and your phone in Airplane Mode (Wi‑Fi and Bluetooth off) so the watch isn’t sitting in a radio storm.
    Sync later once you get a clean recording.
  • Do a quick “pre‑reset” before ECG
    Reboot the Charge 5 (Settings > Device Info > Reboot Device), wait 30 seconds, then run the ECG.
    This clears any hung ECG process that keeps throwing the same F25 code.

If you still can’t get even one clean ECG after all this, the ECG hardware is probably failing, not your technique.

Is It Worth Fixing? (The Financial Verdict)

  • ✅ Fix: F25 only shows up sometimes, everything else (steps, heart rate, GPS) works fine, and the device is in or near warranty.
  • ⚠️ Debatable: ECG is just a nice‑to‑have for you, F25 is random, and the Charge 5 is out of warranty but otherwise solid — you can live with it or upgrade if you really care about ECG.
  • ❌ Replace: F25 appears on every ECG attempt, you also see reboots or other sensor glitches, and the watch is out of warranty or close to the cost of a newer model.

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