Homing error Z #31301 (CORE One) #35301 (CORE One L) #26301…

What happened?

The printer is showing the message: "Failed to home the extruder in Z-axis, make sure the loadcell is working".

Error name: Homing error Z

Error code: #31301 (CORE One) #35301 (CORE One L) #26301 (MK4S) #13301 (MK4) #27301 (MK3.9S) #21301 (MK3.9)

How to fix it?

Forces from filament feeding

Make sure that the extruder is not exerting force to pull down the filament. If you are not sure, try to unwind it a small amount on the spool when testing the Z-axis.

In case you have an MMU, Enclosure, or custom setup where the filament is fed to the extruder by a PTFE tube, make sure that the extruder does not have to exert force to pull down the tube.

Trapezoid nuts

On CORE One and CORE One L, move the bed down, open the trapezoid nuts, and check if they can move freely along the threaded rods.

It is also possible to lubricate the Z-axis lead screws as instructed in Regular printer maintenance (CORE One) under "Axes check - Z-axis leadscrews"


Rear motor	Front left motor	Front right motor

On MK-series printers, check if the trapezoid nuts have the correct orientation.

Loadcell troubleshooting

If the above checks do not solve the issue, it will be necessary to troubleshoot the loadcell and the components surrounding it. The dedicated loadcell troubleshooting article contains all the points to check and that can be related to this error.

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11 comments

yvan levasseur

•

Nozel is not on the bed it pas it

Joshua Brader

•

Same thing happened to me I got a new noseless because my other one got broken

Dan Carmen

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We had this error on the MK4S and followed the loadcell troubleshooting. I believe in our case it was simply a matter of some filament had been ground up by the feed and enough of the filament dust was laying on top of where the loadcell is installed. We took the PG-case off and used a cotton swab to clean off the top of the loadcell, and now everything seems to be working well. It didn't seem like much but I think the loadcell is very sensitive.

Dan Carmen

•

So I was wrong about that. It worked for one print and then started acting up again. We ended up buying a replacement heatsink and loadcell and now it is working for several prints without issues.

Brian Latz

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Yes this article was helpful. I’m not really sure what was going on wrong but I was having issues with the Z height and homing. I went through the test and calibration route twice and the machine would time out during a program start or nozzle cleaning routine. I read the article and followed the calibration sequence again . I re-homed the machine and it has been working fine since.

Vilo

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JellyTitan, You deserve an award! This error jumpscared us at work. Thankfully we found your comment=problem solved. The screws were indeed ever-so-slightly loose. Thank you.

JellyTitan

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For the MK4S, I was able to fix this error by tightening the thumb screws on the nozzle. They had come loose over the course of 6 months, and this was allowing the nozzle to move just enough to cause problems. (I think these loose screws also caused my issues with first layer calibration, crashes during homing, and loadcell calibration).
You can see the thumb screws in assembly instructions step 27, including all three photos, for a guide on proper position and tightening the thumbwheels: https://help.prusa3d.com/guide/5-nextruder-assembly_434014

Vilo

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Sir/Madam, you deserve an award. This error just jumpscared us at work, thankfully we found your comment = problem solved. The screws were indeed ever-so-slightly loose. Thank you.

Vilo

•

You deserve an award! This error jumpscared us at work. Thankfully we found your comment=problem solved. The screws were indeed ever-so-slightly loose. Thank you.

TinyBiggs

•

I have been fighting homing errors and load cell problems for a week. Slight tightening and everything is working great! Thank you for this comment.