OK, I'll answer my own question. Looked in the shop manual and sure enough the error codes only show on the MIB module...which means removing the entire plastic dash cover just to see the code. I guess I could cut a rectangular window in the plastic so I could see the MIB without removing the dash if it keeps happening, but I guess the theory is you might as well have the dash off if looking at error codes as you will probably need to remove it anyway to fix whatever is the actual problem the code is pointing to.