I have replaced the NOX2 sensor. I pulled the DEF injector and it flows well. But I am restricted to 5mph (I had to get where I was going) and my NOX2 readings are -0.6% no matter what NOX1 is. I cannot drive it to reset it. I have regenerated twice. I am aware that does not fix this problem. I am out of ideas and I am too proud to go to the dealer. Any suggestions?