Filament sensor: Fil. stuck #04104 (MMU)

What happened?

When the MMU unit unloads a filament from the extruder, the filament sensor inside the extruder should stop detecting the filament. In case it does not, this error appears.

If there is an issue with unloading, the MMU gears might grind the filament. In case this happens, cut off about 40 cm at the end of the filament; otherwise, errors might happen later.

How to fix it?

Check the PTFE tube that leads from the MMU unit to the extruder, and see if the filament has been unloaded or not.

In case the filament has not been unloaded, make sure that the nozzle is heated for the filament you are using. Then, open the Extruder idler screw and the Festo fitting on the top of the extruder, and manually pull the filament. Note that some force might be necessary.

MK3S/+, MK3.5/S

In case the filament has been unloaded, but the printer shows this error, remake the filament sensor calibration.

Check the alignment of the idler door and the Bondtech gears. On the idler door, check if the gear is moving freely and that the shaft is connected to both sides of the plastic part.

Make sure that there is no debris or pieces of filament in the idler door or extruder gears, causing the filament sensor to falsely trigger.

Remove the PTFE from the top of the extruder and make sure that there is no leftover filament stuck.

Nextruder (MK3.9/S, MK4/S, CORE One)

In case the filament has been unloaded, but the printer shows this error, open the PTFE tube that leads to the Nextruder and check if there is any filament stuck on the top of the heatsink.

Also make sure to clean the filament sensor.


MK3.9/S, MK4/S	CORE One with MMU Lite/CORE One with MMU enclosed

Filament

Check that you are using the correct settings for your filament with the manufacturer. Filaments with stringing may cause jamming.

Before restarting the printer, make sure the filament is straight, cut to a sharp tip, and free of damage over the first 40 cm.

If the issue persists across multiple unloads, check the extruder for clogging.

On the MK3/S/+ and MK3.5/S, in case the issue persists due to deformed filament tips, try changing the PTFE tube.

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4 comments

Lapeno

•

Since FW 3.0.4 it is getting worse

AndrewWert

•

I got this message. RETRY is the only option which does not work. So the print is trash.

honzaprvi

•

I get this error every time the filament is empty. I have to unscrew Ptfe tube an pull out the remaining filament by hand. SPOOL JOIN doesn't work, without my intervention, so it is useless.

Gilles160

•

I have the same issue. Spooljoin option shall not be used

ceesse

•

When this happens, the only choice is "Retry", which is not very useful, as the filament is stuck, so any retry is going to fail again. A second button, like "Abort" would make sense.

Gilles160

•

a "change filament" option would be even better