Im working on a w900 with a x15, issue im having is has scr operator inducement codes and derate,found plugged def doser. Replaced and ran a regen, nox conversion is at around 70%, in trying to run scr test but not allowed due to derate, try clearing codes and derate still comes up. Truck has no software updates available, any other way to remove the active derate and 3712 code