AMS Spool 1 keeps on retracking

I can’t insert my filament in my AMS, The led on the AMS stays red all the time and the AMS keeps on re tracking.
My tool head isn’t clogged, I tested that.
What can I do ?

AMS fault01

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Currently having this same issue. Itll retract the current filament and then when trying to load a new filament through the AMS, it stops near the extruder and then retracts back. Waiting to hear back from Bambu about this.

Thank you, for inform this problem, I hope you will come back if you have an answer from Bambu, meanwhile I search further to tackle this problem.

I can just about guarantee you that you have some filament stuck in the AMS. This just happened to me last night and after emptying the AMS of my spools. I basically followed these instructions and ended up finding a short piece of filament in the internal hub. Jump down to section " 1.1.2 Abnormal AMS internal filament hub" and pull the PTFE tube of the offending slot from the internal hub, betting some filament slides out…

It’s not a difficult procedure, just a pain to do. So far I’ve had to do this about four times since using my AMS.

One thing I’ve noticed, when a print is finished the system retracts the filament and ultimately leaves the filament under tension creating a sharp bend at the point where it exits the funnel the filament feeds into. I just started making a habit of manually back rolling the roll to release this tension if I’m not going to use the filament right away.

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Thank you Larry, I still have no time to do this, but I come back when it’s done…

There was broken filament in the AMS, I removed it like in the
1.1.2 Abnormal AMS internal filament hub” chapter. (Larry’s link)

I would like to know why this happens, Is my filament to old, or wet ?
Or the AMS retracted the filament to hard ???

I had the problem also, mine was old brittle filament. Remove a small piece of filament from the PTFE tub and now working OK. This was for me a lesson learned about using old filament, got rid of that roll and check each old roll I have.

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My filament was new, but maybe old stock??
I don’t know what this new firmware update means, orange arrow…


It must have fixed an issue I had once, where the AMS ran for about 10 minutes before I noticed it. One of the motors kept running after an unload, only a power cycle stopped it.

What people call old filament for the most part is just wet filament.