Hotpoint Dishwasher FDW 60 Circulation Pump Inop

This dishwasher on start up drains then fills. The fault lights flash for circulation pump failure. I have changed the circuit board, checked the cables in the door, placed an independent supply to the circulation pump and it works no problem. I have checked the element, the level/pressure switch to the right hand side and the pressure switch in the sump. Why does the circulation pump not work. Am I missing something stupid.