So I have a 2016 ecodiesel showing a p0402 code and a “service electronic throttle control” message I have replaced the egr cooler and valve, cleaned the egr diffuser, and replaced the map sensor. Any ideas what else could be causing these codes?
Just a guess here but check the throttle butterfly on the front of the intake manifold. If it's not opening up properly, restricting flow of fresh air, that will cause a greater draw from the EGR. Also, check the electrical connectors to it.