Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Remove the connector from the gas valve
Remove the screw completely from the gas valve connector
Attach the gas valve connector to the PCB cover screw pillar as shown in the image using the original screw
Set multimeter to Diode test mode
(click here for how to do this)

Measurement:

Expect a reading of approximately 0.55vdc on each test.
Test 1: Red probe on pin 22 of connector M7 and the black probe on the top pin of the gas valve connector.
Test 2: Red probe on pin 23 of connector M7 and the black probe on the top pin of the gas valve connector.
Test 3: Black probe on pin 22 of connector M7 and the red probe on the bottom pin of the gas valve connector.
Test 4: Black probe on pin 23 of connector M7 and the red probe on the bottom pin of the gas valve connector.