MK4S Unable to verify extruder type error
A MK4S i have stopped working with the "unable to verify extruder type" error #23615.
Printer first showed an error about print fan rpm not detected when I started a new print, fan test failed for the same fan. And after power cycle I get the error.
I tried re-connecting the main cable with no success. I disassembled enough to be able to take a closer look at the cable and boards - and everything seem OK.
I even tried a brand new spare cable I had laying around - same error. Only nozzle block & fans were not connected to when I took the attached photo. I also tried connecting the nozzle block too later with no luck.
Maybe someone has some insights how the extruder type is detected?
I'm at a loss what to try next.
Edit: I'm not sure if it means anything but the printer shows CORE One error code for some reason.