Got it. And again, thanks! I cleared the code before I left from work (I’m driving it now since the S4 is down from the damn deer) and it didn’t come back- which it has done in the past. This lends precisely to what you just described. I’m going to more or less ignore for a bit as I work through the other stuff needing attention.

 

So I did an inspection underneath and found a 2 blade sensor with one unplugged. I plugged it back in and went about some other service. Now the POS thinks there isn’t a MAF hooked up, so I need to diagnose that. I’ll get back to this one eventually…

 

OK, I put the old MAF back in and all is well there. Except…. Yep, the P0501 came back. Methinks that switch that I plugged back into is dead. Going to research and replace as that shouldn’t cost very much. I suspect it’s the High Low switch Richard mentioned.

I did a good inspection of all the wiring harnesses on each side of both the tranny and T case and that was the only suspect one. Some of the sheathing wasn’t perfect, but all wiring looked solid.