My power voltage on the sytem check screen shows 14-14.1 volts. Shouldn't it show 12 volts? I have a 2006 Chevy Silverado 2500 HD Diesel. I suspect the two batteries may be causing this reading. The Z2 works perfectly fine; however, I am concerned since all of the screen shots online show 12 volts. Please advise...

Your truck is fine. Most GM alternators produce 14 volts while running. Turn the truck off and you should get a reading of around 12.5V.