I have a 0401 code and I have already replaced the EGR valve, ran cleaner through the system and about everything else. I have been told to clean the "pipe" and the intake manifold area of the sludge/carbon. Outside of running through a cleaner again, how do I do this? Is the "pipe" the pipe that comes off of the EGR valve? Thanks.
A code P0401 most likely means one or more of the following has happened: There is a blockage in the EGR (tube), most likely carbon buildup
The EGR valve is faulty
The EGR valve may not be opening due to a lack of vaccuum
Possible SolutionsIn fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit.
Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticable difference in RPM's with the EGR open
Clean out the EGR valve and/or tubing to remove deposits