While pulling a load of about 42k #s up some moderate hills, our Volvo dash light came on / check engine light, and says the EMU or something like that needs to be checked. I did some research and it sounds like the 'brain' of the truck or the computer hub is not getting a good voltage reading from somewhere. How can we diagnose the codes or even find the codes? It has a screen that shows a lot of things but we don't see how to know exactly what area isn't reading or sending correctly. Any advise??? Thanks bunches! I am hoping this is covered under our warranty!