Set Appliance State:
Gas Off
Set Multimeter to Resistance 
Isolate Mains Power to appliance as per TOPs P4
Remove the upper electronic flame control device
Remove the upper electronic flame control device
Measurement:
Measure the resistance across pin 3 and pin 4 on the gas valve. Resistance should be approximately 1000 Ohms.
Refit electronic flame control device after test.
Refit electronic flame control device after test.
Isolate as per TOPs P4
and refit as necessary