Iam having problem with 05 sierra 6.0 it seems to be all maf related but i cannot figure out why. First off truck would not turn over 6800 rpm before cutting out or going into security mode and completely turning off engine when the 6800 window was passed .Next noticed converter would not lockup
checked codes and has u 1000 class2 communication failure can clear code and converter will lockup but when test runs code comes back and converter will unlock all with in a mile of driving. I failed the maf at 0 and tested now truck goes into lock up and will shift at 7000 rpm correctly but does still have codes that wont clear ? anyone have an idea whats going on ?

 

Did you by any chance flash a different OS into the 2005 PCM? How do you have the U1000 DTC set-up in the "Engine Diagnostics" > "DTC" table?

 

I did replace pcm but only after u code s came up. I havent changed is set stock not to report error