Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Disconnect lead from pilot solenoid (left hand plug)
(also removing lead for main solenoid may make access easier)

Measurement:

Measure the resistance across the two spades of the pilot solenoid.
Resistance should be approximately 1.5kΩ.