changed egr valve and sensor, but engine light came on again what did I do wrong?

Question

Changed allparts that came with egr and the service light went off but a couple days later it came on again.

Answer 1

P0400 EGR flow malfunction

​ This is where you would have to unplugged the EGR flow from carbon build up, The code that set is a straight forward a restriction of the EGR passage