F11 final spin fault on Whirlpool AWM 8163?

My Whirlpool AWM 8163 has recently developed a fault. During the spin cycle it displays fault code F11 (which I believe relates to a communications error). Before it reaches the point of displaying the fault code eveything seems to work fine (wash cycle, rinse cycle, initial spin cycle) however, in the final part of the spin cycle it seems to spin to an unregulated speed and eventually triggers the fault code - changing the variable spin setting does not seem to make a difference. Additionally, there is a 'clicking' noise coming from the motor which appears to be related to the brushes - with the motor off and the brushes removed no clicking when spun by hand, with the brushes replaced and spun by hand clicking is there. In an optimistic hope I fitted new brushes but this has not solved either the clicking or the F11 fault.
Is this fault likely to be due a main controller board fault, a motor controller board fault or something else?