So I pulled the MCU out of its plastic housing and there was a scorch mark on the housing as well as a smaller burn mark on the circuit board. I didn't see any bulging caps, but there was definitely an incident of some kind there. I replaced the MCU and it is working great now. I also had another question though - the diagnostic test is definitely different than described in the tech note. I'm trying to correspond with servicematters about this, but I don't want to pay $500 for a subscription just to help them update their docs. Is anyone with a servicematters.com subscription interested in taking up this matter?