Sonos Arc Soundbar F56 Error Code Fix Guide

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What This Error Means

On a Sonos Arc, an F56-type fault almost always means a problem on the HDMI ARC/eARC link between the soundbar and the TV.

Translation: the Arc and the TV are not talking cleanly over ARC/eARC, so audio cuts out, refuses to start, or keeps dropping.

Official Fix

Do the boring, textbook stuff first. This is what Sonos and the TV manual expect you to do.

  • 1. Make sure the Arc is on the TV’s ARC/eARC HDMI port.
    • Check the labels on the TV’s HDMI ports. One will say ARC or eARC.
    • The Sonos Arc must be plugged into that exact port. If it is not, move the cable there.
    • Power the TV off and back on after you move it, then test sound again.
  • 2. Eliminate a bad HDMI cable.
    • Use a short, decent High Speed or Ultra High Speed HDMI cable, ideally 2 m / 6 ft or less.
    • If the cable is thin, ancient, or a random freebie, assume it’s guilty and swap it.
    • Test with a different, known-good cable. If F56 or the dropouts vanish, the old cable was the problem.
  • 3. Hard reboot the TV and the Sonos Arc.
    • Unplug the TV and the Arc from power for at least 60 seconds.
    • While the TV is unplugged, hold its power button for about 10 seconds to dump any leftover charge.
    • Plug only the TV back in first. Let it fully boot to live TV or the home screen.
    • Then plug the Arc back in. Wait until the light settles and the Sonos app sees it.
  • 4. Fix the TV’s audio and HDMI settings.
    • In the TV’s Audio or Sound menu, set Audio Output to HDMI ARC or eARC, not “TV speakers”.
    • Turn on HDMI-CEC (brand names: Anynet+, Simplink, Bravia Sync, VIERA Link, etc.). The Arc needs this.
    • Enable eARC if your TV has a separate eARC toggle.
    • Set Digital Audio Format to Auto, Pass-through, or PCM. Avoid strange re-encode modes.
    • Turn off any optical audio output setting if you’re using HDMI ARC, so the TV stops trying to split audio.
  • 5. Re-run TV setup in the Sonos S2 app.
    • Open the Sonos S2 app on your phone or tablet.
    • Go to Settings > System and tap the room with the Arc.
    • Run the TV/remote or input setup again so the Arc re-learns the TV and handshake.
    • Clear any warnings in the app, then test with a built-in TV app like Netflix or YouTube.
  • 6. Update firmware on both the TV and the Arc.
    • In the Sonos app, check for system updates and install everything it offers.
    • On the TV, run a software/firmware update from its Settings menu.
    • After updates, power-cycle both again (TV first, then Arc) and test.
  • 7. Test the Arc on another TV if you can.
    • Hook the Arc to a different TV that has an ARC/eARC HDMI port.
    • If it works perfectly there, your original TV is the weak link (HDMI board or firmware).
    • If the same F56-type behavior follows the Arc to every TV, the Arc itself likely has an internal fault.

If you have done all that and the F56-type error still comes back, the official move is: grab a diagnostic in the Sonos app and open a ticket with Sonos Support so they can check for internal hardware flags.

The Technician’s Trick

When the “by-the-book” steps fail, the real culprit is usually a scrambled HDMI-CEC / ARC handshake. Here’s how techs reset it for real.

  • 1. Kill power to everything in the HDMI chain.
    • Turn off the TV, the Arc, game consoles, streaming boxes, everything.
    • Unplug all of them from the wall. No standby, fully dead.
  • 2. Pull every HDMI cable out of the TV.
    • Unplug every HDMI device from the TV. Leave the TV with zero HDMI connections.
    • Wait 2–3 minutes. Give the HDMI/CEC controller time to fully discharge and forget old pairings.
  • 3. Bring the TV and Arc up alone.
    • Plug the TV back into power and turn it on with no HDMI cables attached yet.
    • Once it’s booted, plug the Arc into power and connect it to the TV’s ARC/eARC port only.
    • In the TV menus, re-enable HDMI-CEC and ARC/eARC if they got toggled off.
    • Play sound from a built-in TV app and see if the link now stays solid.
  • 4. Reconnect other HDMI gear one at a time.
    • Connect one device (cable box, console, etc.), then test ARC again.
    • If ARC dies right after plugging in a certain box, that box’s CEC is hijacking things.
    • On that device, disable its HDMI-CEC setting, or run it through an HDMI CEC blocker adapter.
  • 5. Dial back the audio format if it only chokes on heavy content.
    • If problems show up only with Dolby Atmos or high-bitrate movies, set the TV’s HDMI audio from bitstream/TrueHD down to Auto or PCM.
    • This lightens the HDMI load and often stops the F56-style failures while still giving you clean sound.

That full CEC/ARC reset is the “inside baseball” trick that fixes a lot of stubborn F56 HDMI headaches that survive the official playbook.

Is It Worth Fixing? (The Financial Verdict)

  • ✅ Fix: The Arc is under 5–6 years old, the issue only appears with one TV, and a new HDMI cable plus proper settings make it mostly stable or fully clean.
  • ⚠️ Debatable: The Arc is out of warranty, your TV is older and already flaky on HDMI, and you may be staring at both a TV HDMI board problem and a possible paid Sonos swap.
  • ❌ Replace: F56-type faults follow the Arc to every TV, Sonos confirms an internal hardware failure, and their out-of-warranty replacement price is close to buying a newer soundbar outright.

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See also

Got other gear screaming error codes at you? These guides can save more time and swearing: