Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Disconnect one of the orange wires from the sensor

Measurement:

Measure the resistance across the exposed terminals of the sensor.
The resistance depends on temperature and should conform to the table below:
Temperature °CResistance in kOhms
20 - 3010.0 - 6.0
30 - 406.0 - 4.1
40 - 504.1- 3.1
50 - 603.1 - 1.8
60 - 701.8 - 1.2
70 - 751.2 - 0.9

Reconnect wire after test.