Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector CN2 from the PCB
Remove the electrical connector from the gas valve

Measurement:

Test 1.
Measure the resistance between the brown and
blue pins on connector CN2.
Test 2.
Measure the resistance between the brown pin on
connector CN2 and a suitable earth connector.
Expected resistance greater than 1 MOhm for each test.
Note.
A reading of O.L is acceptable as this is greater than 1 MOhm.