The aftertreatment system for this engine is not activating. There is an error code 2771 about the NOx sensor. We changed the sensor but the code is still there. The truck loses power going up hills. Anyone know how to solve this or to troubleshoot the def system?
You will need software to figure this out. Which nox sensor is giving the fault? What is the specific definition for that code? Any other fault codes active or triggered recently and not active? Are you using more def than usual? Teir4 is a real pain and seems to be looking for a reason to be unhappy. Without these answers it would be hard to steer you in the right direction.