I had a P401 error code for "EGR flow insuffecient". I first changed the EGR valve. Error code came back. I then changed the DPFE valve, cleared the computer and the error code has come back again. Does anyone else have any suggestions?

try cleaning egr valve and passages with carb cleaner. i had the exact problem and a few cans solved it

I tried your rememdy. Cleaned the intake with carb cleaner, cleared the computer, and the darn light came back on. So far I have changed the EGR, DPFE and cleaned the intake behind the EGR. Any other suggestions out there to take care of a P401 code?

same thing happened to me
its back on now and i have replaced the same things also. any other opinions would be nice