why am i still getting the po401 code what else coud the cause be?

Question

I have replaced the egr valve and the dpfe sensor or it is sometimes called the egr feedback sensor and am still getting the insufficient flow code any suggestions please.

Answer 1

P0401 EGR recirculation flow insufficient detected

Check the solenoid for the EGR, the vacuum line is shared with the heater control valve any break in this vacuum line will make the EGR flow insuffiecient, and so can this valve being non operational.