Step 1. Disconnect the thermocouple from the gas valve.
Step 2. Using a multimeter capable of measuring ohms (or continuity), attach one lead using an alligator clip to the pilot tube. Insert the other lead fully into the magnet opening, be sure the lead makes contact only at the top center of the magnet opening.
DO NOT allow the lead to make contact with the threaded sides of the opening.

Step 3. If continuity is indicated, the ECO is O.K.. If continuity is not indicated, the ECO has opened, and the gas valve must be replaced.