Update: I just looked up the specs in my ALLData subscription and the operating value is listed as 0.0 - 1.25V and at idle about 0.1 - 0.9V

I would say that based on that information, the readings I'm seeing in the log files are normal (thus no check engine light).

I still don't know if there is a definitive test to isolate the problem.

 

Are you saying the CEL hasn't come back on? Most troubleshooting trees start with clearing the codes & waiting to see if they even come back at all.

 

It does come back on eventually. One time it came back on the very next day, and another time it took several weeks before it came back on. The only thing that is constant is that it hasn't come back on while I am testing. Ugh...