Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector X25 from the PCB
Remove connector from the Mass Flow Sensor

Measurement:

Measure the resistance across each wire in the harness from the PCB to the Mass Flow Sensor at the connections stated below in the table.
Pin on connector (X25)Mass Flow Sensor Connector
12 (Green)Green
6 (White) White
9 (Red)Red
7 (Black & Blue)Black

Expect continuity on each of the wires in the harness.
Also visually inspect the harness.
Note:
Each pin on the PCB connector is numbered.