Prusa Error 13846: Nozzle Cleaning Failed
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Prusa error 13846 means the automatic nozzle cleaning routine ran and did not achieve a clean tip. Prusa’s own message flags that auto-retract being disabled may be the cause. In practice it is usually a blob too large for the wipe to remove, a worn wiper pad, or auto-retract switched off so filament oozes straight back onto the nozzle.
The cleaning step exists because these printers probe with the nozzle. A clean tip is not cosmetic here — it is a prerequisite for the machine knowing where the bed is.
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- Clean it by hand, hot. Heat to printing temperature and use a brass brush. The automatic wipe is designed for residue, not for a large blob — the full method is in nozzle cleaning.
- Re-enable auto-retract. Prusa name this explicitly in the message. Without it, filament oozes back onto the tip during the move to the cleaning area.
- Inspect the wiper. The silicone or brush pad wears down and eventually stops making contact.
- Check the temperature in the profile. Cleaning works in a narrow window; too cold and the plastic does not release from the tip.
Why blobs form in the first place
Oozing between prints, a partially clogged nozzle, or wet filament bubbling at the tip. If you are cleaning frequently, the cause is upstream — a partial blockage produces exactly this pattern, and so does filament that has absorbed moisture, which drying resolves.
What it breaks downstream
A failed clean usually turns into 13833 bed levelling failed a minute later, because the probe is reading through a dirty tip. Fixing the cleaning step fixes both.
This error reads 31846 on CORE One, 35846 on CORE One L, 17846 on XL and 16846 on iX.
Prusa Error 13846 FAQ
What is auto-retract and why does it matter here?
It pulls filament back slightly when the hotend is idle so it does not ooze. With it off, the nozzle re-coats itself on the way to the wipe.
Can I skip the cleaning step?
Not sensibly on a loadcell machine. The probe reads through the nozzle tip, so a dirty nozzle gives a wrong bed height.
How often should the wiper be replaced?
When it stops visibly contacting the nozzle, or when cleaning starts failing regularly. It is a consumable, not a permanent part.
Why does this happen more with some filaments?
Filaments that ooze more — PETG especially, and anything damp — leave more on the tip between prints. Drying the spool reduces it.
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