Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove the ignition control box from the gas valve

Measurement:

Test 1:
Measure the resistance between pin 1 and pin 4 on the gas valve (top and bottom)
Resistance should be approximately 8 kOhms.
Test 2:
Measure the resistance between pin 1 and the earth pin.
Resistance should be greater than 1Mohm.
(O.L is acceptable because this is greater than 1Mohm)
Are the resistances measured as expected?