Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector X2 (detection electrode lead) from the PCB

Observation:

Test 1.
Measure the resistance of the detection electrode and lead,
electrode to PCB connector.
Expect continuity / zero resistance.
Test 2.
Measure the resistance at the detection electrode to a suitable earth point.
Expected resistance greater than 1MΩ (or O.L.)
Note.
Ensure a good connection is made or misdiagnosis will occur.