AMS cannot retract filament

My machine is broken down and there is no obvious override for the loop I’m in.

It had a problem cutting filament. That was overcome. If I bypass ams it prints.

With the ams it tries to cut non-existent filament then fails to pull the non-existent filament back.

I cannot manually feed the filament from the ams to the head. I pushed a length of filament back into to the ams and from the ams out. The two pieces touch inside the ams. Seems no blockages. Is there no way to force the ams to push filament all the way to the head?

To be honest: I don’t really understand your problem. But if I unterstand (at least your last question) correctly, I think “loading filament” in the AMS settings will force the ams to push the filament all the way to the nozzle.

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Nope. It tries to cut filament then retract filament before it loads. The retraction fails. Seems a simple override would work. Just an error message.

I am encountering much the same issue. There are no blockages i can find in the printer nor ams but it is unable to feed the filament out of the ams automatically and gives me an error “Failed to pull out the filament from the extruder … [0700 8003]”

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I think I found the source of the error on my machine. The green circle on the extruder icon on the touch screen menu never goes away even when there is no filament (stuck or otherwise) in the extruder. The filament detection hammer is stuck and won’t move back in when the filament is gone causing the printer to always think filament is present.

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Where is this filament detection hammer? I’ve been struggling without an AMS for over 10 days. It’s a very expensive paper weight right now.


In the filament feed there is a small hammer under the small magnetometer pcb that detects the filament. If it doesn’t depress into the device, then it always thinks filament is stuck in the system.

If you look in the videos for Extruder Clog | Bambu Lab Wiki , the hammer is in the small magnetometer board to the side of the filament drive assembly. You can tell it is stuck when the green light on the dashboard screen for the extruder does not go away when no filament is present.


you have to take apart the entire filament feed system, Because bambu cant manage to output a coherent error message telling you which sensor the machine is obviously reading as having filament. This level of incoherent errors is unreal on a $1600 machine.

Mine was determined to be the filament sensor itself. The side walls are not smooth enough. The fins on the metal part got stuck. I pressed them away from the walls with a screw driver until the filament could retract without causing the sensor to stick.

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