Miele intergrated fridge.

been to a Miele K851 iD fridge, although its reaching temp ok, the fan function is not working. The fan itself is fine. after I switched off and, later, back on again it flashed F then 0 for about a minute before starting up, still no fan when button is pressed. assume a sensor or the pcb is down and it is in some kind of emergency mode. Anyone come across this before and know the solution? thanks in advance..