2006 Duramax P0401 & P0402 DTC Code
 

My check engine light came on today so I put my Bully Dog tuner on and codes P0401 and P0403 came up. From what I have found out it is something related to the EGR. If so does it mean that it's pluged? It has 32750 miles on it.

Did some research and these are the fixes I have come up with:

-Check the voltage at the DPFE sensor both at idle and when the EGR is open
-Replace DPFE sensor

• 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
• Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model)
• Replace the DPFE sensor (with a good quality / OEM one)
• Replace the EGR valve

I don't know what all this means, but maybe you do... :/

Thanks Kevin.