No filament feeding to the extruder; parts already replaced

Bambu Lab P Series Bambu Lab P2S
1

Hi, I’m writing this in German; I hope it still makes sense after translation :slight_smile:

I have a P2S printer with AMS; it currently has about 600 hours of operation, and I’ve used around 25kg of PLA/PETG filament so far.

For the last two weeks, I haven’t been able to print a single part correctly because I keep getting alerts stating that the extruder cannot feed the filament and the print needs to be aborted.

  • I’ve removed, cleaned, and reinstalled the extruder several times.
  • I’ve cleaned the hotend multiple times.
    Unfortunately, with no success… I manually set the extruder to 250°C and fed a piece of filament in by hand; the extruder works fine in that regard.

I then ordered and installed replacement parts:

  • I replaced the extruder gears.
  • I replaced the 0.4mm hotend.
  • Nothing else shows signs of use.
  • The AMS feeds filament without issues.
  • The tubes aren’t damaged or dirty.
    Again, unfortunately, with no success…

I’ve also tried different filaments—though I only have PETG on hand. I dry the filament at 65°C for several hours, resulting in a residual humidity level of 10–15% in the AMS, but still, no success…

Can anyone help me figure out what else to do? I’m pretty stumped, especially since I just successfully processed 5kg for a modeling project without any issues. Even that remaining filament won’t feed anymore…

Any ideas?

Greetings from Germany,
Christian

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Hallo, ich schreibe den Text auf Deutsch, ich hoffe er ergibt nach der Übersetzung noch Sinn :slight_smile:

Ich habe einen P2S-Drucker mit AMS, aktuell circa 600 Betriebsstunden, circa 25kg PLA/PETG Filament habe ich bisher verarbeitet.

Die letzten 2 Wochen habe ich kein einziges Teil korrekt drucken können, weil ich darauf hingewiesen werde, dass der Extruder das Filament nicht fördern kann und daher der Druck abgebrochen werden soll.

  • Ich habe den Extruder mehrfach ausgebaut, gereinigt, eingebaut.
  • Das Hotend habe ich mehrfach gereinigt
    leider ohne Erfolg… Ich habe manuell den Extruder auf 250°C gestellt und ein Stück Filament manuell zugeführt, soweit funktioniert der Extruder.

Jetzt habe ich Ersatzteile bestellt und eingebaut

  • Das Extrudergetriebe habe ich ersetzt
  • Das Hotend 0,4mm habe ich ersetzt
  • alles andere weist keine Verschschleisspuren auf
  • Das AMS fördert das Filamen ohne Probleme
  • Schläuche sind nicht geknickt oder verschmutzt
    wieder leider ohne Erfolg…

Ich habe auch verschiedene Filamente probiert, ich habe aber nur PETG da, ich trockne das Filament bei 65°C mehrere Stunden, habe dann eine Restfeuchtigkeit im AMS von 10-15%, aber wieder leider ohne Erfolg…

Kann mir jemand weiterhelfen, was ich noch machen kann??? Ich stehe hier ziemlich ratlos, obwohl ich für ein Modellbauprojekt grade erst 5kg ohne Probleme verarbeitet habe. Auch dieses Restfilament lässt sich jetzt nichtmehr fördern…

Jemand eine Idee???

Grüße aus Deutschland
Christian

2

A quick follow-up: Sometimes the jam occurs after 2 minutes, sometimes after several hours of printing…

I measured the filament, and the thickness is fine.

=====================

kleiner Nachtrag: Manchmal passiert der Stau nach 2 Minuten, manchmal nach meheren Stunden Druckzeit…

Das Filament habe ich nachgemessen, die Dicke ist ok

3

If you’ve replaced many parts, it’s a good idea to reset the printer to its factory defaults and recalibrate it. It’s possible that your printer is still calibrated for the old parts. You don’t necessarily have to do it, but I personally would start with that.

To rule out the AMS, I would try not to use it - if possible - and simply hang the spool on the external mount for the time of calibration.

So, step one: Reset the printer and perform the printer calibration.

Step two: Perform the separate calibration in Bambu Studio:

Screenshot 2026-07-25 065242
Screenshot 2026-07-25 0652421920×1332 269 KB

Then check the result: it should look something like this:

Screenshot 2026-07-23 151350
Screenshot 2026-07-23 1513501920×914 348 KB

This doesn’t address your actual problem yet, but at least it gives us some common ground. Please take a photo of what the calibration results look like - that often helps identify the problem. Also, whether the filament feeding problem occurs during calibration!

This brings us to the actual problem:

Please take a photo or write down exactly which error code the printer is displaying.

Possible causes include:

  • Fine filament debris from wear and tear that can contaminate the sensor or drastically increase friction in places you can’t see. That’s one of the most common causes, so you need to know how thoroughly you cleaned everything.
  • If the printer is in operation for a long time, the tubes can wear out and become rough inside. If this is compounded by an unfavourable configuration or improper routing of the tubes, the friction will also be too high, resulting in an error message.
  • The sensor is defective or has a loose connection. It’s rare, but it does happen.

I would try to cleaning it really thoroughly again, because it won’t cost you anything. Then, if necessary, replace the tubes, since they’re really cheap to get. Incidentally, cutting tubes at an angle rather than straight can also cause this kind of problem over time. Only if all else fails should you consider the sensor.

Maybe you’re really lucky, and it’s just a piece of filament or some debris near the sensor.

If you can reproduce the fault, please be sure to check whether the toolhead logo rotates and whether you hear a loud clicking sound. If that’s the case, the extruder isn’t grabbing the filament for some reason.

Here’s a guide for the sensor:

You can also take a look at the general guide to the extruder on the wiki to see if you did anything differently: