I have a Jandy legacy natural gas heater that is giving me an ignition fault and will not light. I have followed this problem flow chart from this link (click on downloads tab, and it's on the bottom of the page under H0299500.pdf) and it seems I am not getting voltage between ground and where the brown wire connects to the gas valve (this is on page 41 of the pdf). I followed the troubleshooting parts up to the Gas Valve Voltage (10.4.3.6) and everything prior to this is OK.
So my thinking id it's either the ignition control module or the circuit board that it hooks up to. Is there a way to tell which of these might be the problem?