Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove ignition lead from electrode
Remove ignition lead from PCB

Measurement:

Measure the resistance between either end of the ignition lead using the brass connector inside the spark cap.
Expect approximately 1kohm.
Also visually inspect the ignition lead and cap.
Are the lead and cap in good condition and is the resistance as expected?