Not much you can do, you’re going to need to verify the ECM has the ability to open and close the purge valve. You can manually apply power and ground to the purge valve to verify if it has the ability to open and close but without a bidirectional scan tool that about all you can do.

One caveat is you could technically watch scan data and wait till the ECM to command the purge open on its on to check for power and ground at the purge. You’d need your test setup in place and just run the truck watching for the purge to be commanded open on scan data.

I’m assuming you’ve already replaced the purge valve and the code came back… If so make sure you didn’t just get a bad new purge valve, they like to be DOA straight from the box in my experience.