Hello,
I have the K2 Pro Combo and keep getting the error message BM2355.
Can anyone help me here in the forum?
Best regards,
Stephan
Hello @Elimar2004 
Welcome to the Creality Forum…! 
I don’t know if this helps but the cable to the hot end seems to be a weak link on some of these printers causing the MCU communication error.
I have the K2 Pro Combo and haven’t had that error yet.
Creality has a video here 
K2 Pro Hotend Adapter Cable Replacement
You might not have to replace the cable but the video shows the parts that might need to be checked for looseness.
Brand new K2 Pro here, will not pass initial setup and calibration with same error BM2355 MCU error.