Help Needed: X1C - Extruder Clog Error When Loading Filament

I’ve been using my X1C for the past few days to print small boxes for organizing my son’s LEGO collection, and everything was running smoothly. I was using up some leftover filament from Overture and Hatchbox, mixed with some Bambu filament, and even switched over to a 0.6mm nozzle without any issues.

Once I ran out of the Overture and Hatchbox filaments, I switched fully to Bambu Labs filament. I’m working on a keyboard shell for a hand-wired project, so I loaded up some Bambu Labs PLA Basic blue filament, sliced the STL, and started the print. About 10 minutes in, the print stopped. I hit retry, and it stopped again shortly after. Eventually, I swapped the PLA for some Bambu Labs PETG HF filament, but the same thing happened. I kept getting an “extruder clogged” error on the printer screen.

I wasn’t sure if it was the nozzle or the extruder, so I started by swapping the 0.6mm nozzle for a 0.4mm one, but the issue persisted. I followed some troubleshooting steps for clogged nozzles—heated the nozzle to 235°C (PETG temp), extruded manually, and the filament flowed through fine. Tried another print, but same error. Did another manual extrusion, cooled to 100°C for a cold pull, and it looked good, but the clog error came up again.

At this point, I didn’t even need to start a print—just loading the filament was enough to trigger the extruder clog error.

Next, I disassembled the extruder (super easy process, by the way—props to Bambu for the great tutorial and design). Everything looked clean inside—no strings, chunks of filament, or dust. The gears showed no visible wear, and they grabbed the filament fine when I manually tested them. Reassembled everything, tried loading filament again, and still got the same error.

I went online to see if anyone else had this issue and found some posts about the extruder sensor. They suggested checking if the extruder icon in Bambu Studio turns green or grey when filament is inserted. I pushed the filament in manually, and the icon is black. .

So, now I’m stuck. Any ideas on what might be going on? I figured it’s time to reach out and see what you fine folks think.