Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Disconnect pump plugs from PCB

Measurement:

Measure the resistance of the pump wires to the pump neutral (blue wire).
Resistances should be approximately as below:
Brown to neutral: 11.3kΩ
White to neutral: 2.2kΩ
Purple to neutral: Greater than 1MΩ
Black to neutral: 3.2kΩ