I've had this P0401 code on my truck since roughly 2012, and I haven't been able to solve the issue since. I got a rebuilt turbo less than 10,000 miles ago, I soaked the EGR valve in carb cleaner less than 1,000 miles ago, cleaned the carbon from the intake, cleared the codes multiple times, and that warming amber glow has never left my side. It hasn't really affected how the motor runs (but it did clear up a good bit when I cleaned the EGR valve), but I'd still like to get rid of that light for the first time in nearly a decade. Y'all got any ideas? Thanks, Owen.
P.S. I've also had a P1876 code for a while too but that's not as urgent for me. It also hasn't noticeably affected the functionality of the 4WD system at all, but again I would like to have no codes left on the computer.