The CFS detects the filament and turns the blue light on, but it does not auto-feed. When I press Extrude, it retracts the filament instead

Flagship K Series Creality Flagship K2 Plus & CFS
1

K2 Plus CFS detects filament but does not auto-feed

Hi, I’m having a problem with the CFS on my Creality K2 Plus.

I wanted to change the filament in slot A1. I retracted the old filament normally and removed it without any force. Then I inserted a new filament until the CFS sensor detected it and the blue light turned on.

However, the CFS did not automatically pull the filament in. When I pressed “Extrude”, instead of feeding the filament forward, the motor seemed to run in the opposite direction and pushed/retracted the filament back out.

We tried this several times. Later, we opened the back of the CFS and found a small broken piece of blue filament inside, which we removed. After reassembling everything, the problem was still there.

We then tested the same new filament in another CFS slot, and that slot also stopped auto-feeding. Now the CFS still detects the filament and the blue light turns on, but the feeder motor does not pull the filament in automatically.

We also tested with other filaments that previously worked, but the affected slots still do not feed correctly.

Has anyone experienced this issue? Could this be related to the filament feeder module, a filament sensor, or the CFS photoelectric/hub board?

Thanks for any help.

2

When loading the filament, are you only pressing extrude when putting it into the cfs? Once you put it into the cfs and the light shows, click filament make sure the name is set and hit “LOAD”. That should do it for u. Extrude works when it’s already loaded.

3

I had this problem with CFS and I checked the entire pathway and found a minute piece of filament in the tubing at the feed motor. It causes the sensor to say there is a filament inserted so the filament to are trying to feed will retract instead of extrude. Check the pathway from tubing, motors, and buffer.

4

Perfecto, la redacto ahora en inglés, clara y breve.

Title: Creality Hi Combo – CFS Feeding Backwards Instead of Loading Filament (SOLVED)

I wanted to share a solution to a problem I experienced with my Creality Hi Combo and its CFS system, in case it helps someone else.

The problem:

After one of my PLA spools ran out, I inserted a new spool into the CFS. The system detected the filament (the indicator light turned on), but it wouldn’t automatically feed it.

When I selected “Extrude” on the printer, the CFS motor actually rotated backwards instead of feeding the filament forward.

The cause:

I discovered that approximately 2 cm of PLA from the very end of the previous spool had broken off and remained stuck inside the CFS.

The last section of filament on a spool is usually bent where it is secured during manufacturing. This creates a weak point that can break when the spool runs out.

In my case, that small piece broke off and remained inside the lower filament pathway of the CFS, near the filament detection sensor.

As a result, the CFS incorrectly detected that filament was still present and wouldn’t load the new material properly.

The solution:

  1. I disconnected the CFS.

  2. I inspected the underside of the unit.

  3. I disconnected the plastic PTFE tubes underneath the CFS.

  4. I found and removed the approximately 2 cm piece of broken PLA.

  5. I reconnected everything and loaded the filament again.

Result:

Everything started working perfectly. The CFS immediately recognized and loaded all the PLA filaments correctly.

My recommendation:

If your Creality Hi Combo CFS detects filament but refuses to load it, or the feeding motor rotates backwards when you try to extrude, check the PTFE tubes and filament pathways underneath the CFS before assuming there is a motor or electronic failure.

A broken piece of filament from an empty spool might be causing the issue.

I hope this helps other Creality Hi Combo owners avoid unnecessary troubleshooting!