Set Appliance State:

Set Multimeter to Resistance Set meter to measure resistance
Isolate Mains Power to appliance as per TOPs P4
Remove the two Brown wires from connections EV1 and EV2 and the Blue wire connected to connection marked COM on the main gas valve solenoid.

Measurement:

Test 1:
Check resistance across EV1 and COM is between 800 - 1000 ohms.
Test 2:
Check resistance across EV2 and COM is between 800 - 1000 ohms.
Reconnect wires to Operator Solenoid.