Stop engine and check engine light wont clear

[Crod]

2012 freightliner M2 with cummins isb 6.7 Both check engine light and stop engine light on truck derated to 5miles an hour i put computer to clear codes but lights wont clear on dash board i also did a force regen but state continue to stay inhibited i then unplugged a harness directly under the cab on the drivers side and removed some sensors on the def side of things and the computer did not give any codes but when i unplugged sensor not related to def the computer did give codes any ideas on what can be wrong??? Thanks for the help