Set Appliance State:

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

Measurement:

Test 1.
Measure the resistance between the 2 pins on the gas valve connector.
Expected resistance approx. 9.3 KOhms.
Test 2.
Measure the resistance between the brown wire on the
gas valve connector to a suitable earth point.
Expected resistance greater than 1 MOhm.
Note.
A reading of O.L on test 2 is acceptable as this is greater than 1 MOhm.