CM2798 Error - intermittent - e axis

Flagship K Series Creality Flagship K2 Plus & CFS
1

So, I’ve managed to print a total of about 6 things from my K2(including benchy). While I’ve been impressed by the quality of the prints themselves(I’m new to 3D printing) when I manage to print, I can’t say things have been smooth exactly. When I bought the printer and received it from Best Buy I had the issue with the door where the top hinge had come unglued during shipping(a sincere thanks to Creality support for shipping me a new one). Creality doesn’t control what happens during shipping so I give them a pass on that, and it’s evident they did do a LOT to secure the printer to prevent damage during shipping…as to be expected from a $1600 piece of hardware.

With the exception of a filament jam that I had to clear from the Extruder when printing with PETG filament for the first time, things had been going relatively smoothly. But then things changed. After clearing a clog in the extruder, I first encountered this error message, after turning the unit back on, I received a CM2798 error during the units POST. It just says “e axis step-servo motor initialization error, motor communication line may be corrected incorrectly” on the screen and then it presents the generic XS2001 error code repeatedly.

After tearing apart the extruder again, and struggling to remove the PETG hose from the compression fitting at the extruder, and verifying all the cable connections were connected properly- I gave up troubleshooting that night after encountering this error repeatedly- I gave up defeated and gave it 24 hours so I could calm down. Then suddenly when I turned it back on the CM2798 error had cleared on its own and everything had been fine…until yesterday, when I turned on the printer and it presented the same CM2798 error again. And so I checked the connections again and after failing to resolve the issue I powered it off again, then today I turned it back on and got the error once again.

I checked the connections at the extruder assembly again, and they all appear to all be connected from what I can see, but after giving it another day to clear the error persists so something’s wrong somewhere and I’m far from an expert on 3D printers.

Any ideas what I need to check?

2

This smells like a hardware issue with one of the PCB connectors, or possibly a wire broken off inside the insulation in one of the hotend cables. I had a similar issue which turned out to be a poor solder joint on the filament sensor connector. In my case it finally failed “hard” when the connector came adrift from the board. Fortunately Creality sent a spare filament sensor board with the printer, so I was back up and running again quickly. In your case I would suspect the motor cable or more likely the hotend pcb. It may also be the extruder motor itself. Given your shipping damage, it’s possible that the same shipping rough handling caused more damage to cables/connectors etc, but it’s more likely to be a manufacturing fault. (in my case it looked like an assembly fault, where the filament sensor cable was compressed against the connector during assembly).