Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Disconnect electrical connector from gas valve

Measurement:

Test 1: Measure the resistance pin 1 and 4 of the gas valve.
Expected resistance approximately 7.1k Ohms.
Test 2: Measure the resistance between pin 1, 3 and 4
and a suitable earth point.
Expect resistance greater than 1M Ohm on each pin.