Cummins ISB eng.code 2777 Inhibited ?

I have been working on a 2012 Freightliner med duty Vin#FB1187 with a cummins ISB epa 10 2250 Ser#73409156. The trk comes to the shop with checkengine light on after about a month of driving. Soot levels are high . Run force regen and a afttertreatment regen analyzer test which it passes. Can not clear code 2777 "regen inhibited due to inhibited condition exists " and code 3753 . The vehicle will not passive regen thats why it is back every month .Went into Parameters and see the inhibited switch is disabled. I can find nothing wrong with the trk to lead to why it will not passive regen. Any ideas of what I may be missing ? Thanks