Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove the detection electrode from the burner door and disconnect at the in-line connector

Measurement:

Measure the resistance of the electrode and lead and visually inspect for damage.
Note:
Before reassembly, check the integrity of all disturbed gaskets and seals and replace as necessary.