Since diesel engines do not have vacuum the power brakes need a way to get power.. this is done from a line from the power steering.. I would not think that is the problem. Maybe the computer sensed a power train fault and put the truck in "limp mode" then the fault cleared and things returned to normal.. Have the dealer with a proper scan tool check the codes..
2004 Chev Silverado Duramax optioned past the max. 2009 Jayco Eagle 308 RLS 765 watts of solar, 6-6 volt batteries (696 amp hour), 2000 watt (4000 surge) whole house inverter.
215 days boondocking in 2016
211/2015, 196/14, 247/13, 193/12