I had a jam at the filament guide of the left nozzle, and thanks to user_1083141284, I was able to fix it. Unfortunately, now that I reassembled everything, the extruder won’t switch to the left nozzle. The blocker moves freely left and right, but when it is at the right position, you can hear a not loud clicking sound, and I get the ( HMS_07FE-8000-0002-0001: The lifting action is abnormal during the extruder switch. Please check whether the flow blocker is stuck or there is filament stuck in the toolhead) error.
Update: I found the root cause. A small molten piece of filament had fallen to the bottom of the nozzle rail guide and was preventing the left nozzle from traveling all the way down during the switch.
This happened because of the original filament guide issue. The filament was sticking out in front of the left nozzle, and when it heated up, a small molten bit dropped down behind the heating element and into the lower rail area. From the outside everything looked normal and the blocker moved freely left and right, but the lifting action could not fully complete because that tiny piece was physically stopping the nozzle from reaching its full down position.
I removed the nozzle and the heating element assembly to properly access the bottom of the rail. Once I cleared the small molten fragment, the nozzle was able to travel fully and the extruder switch started working normally again. The HMS_07FE-8000-0002-0001 error is gone.
If anyone gets the lifting action abnormal error after a filament jam near the guide, check carefully for small molten debris behind or below the heating element, even if the mechanism looks fine at first glance.
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