Shawn.G,   Glad to hear you got the issue resolved. To answer your question, I believe that is a board based voltage sensor, associated to the chipset.
After updating the iDRAC(express) to 2.9 and the Lifecycle controler to 1.7.5.4 (prior was 1.2 on the iDrac).  I have started getting the system to log this error and it powers off, which is expected if it is overheating. I have been unable to locate information about the IOH1 if it is on the CPU or system board and if the 1 in the log referring to CPU1. Current config: 2x x5675 processors with 192gb ram, perc h700 with 8 drives, 2x 1100w power supplies Any help is appreciated .
PowerEdge T710 IOH1 themtrip voltage out of range