Continuous P0401 Code - 2008 Explorer 4.0L

[08TXExplorer]

Hi All,

I continue to get the dreaded P0401 code after several 'fixes'. Here is what I have tried to alleviate this issue:

- Replaced the EGR - single unit that has the sensor and solenoid on top.
- Replaced the vacuum houses from the EGR to the intake manifold (the old ones were brittle and one snapped in half causing the replacement).
- The item above cause the removal of the intake manifold which resulted in replacing the intake manifold gaskets. I also replaced the PCV since it was due.
- I removed the throttle body and cleaned it well - it was quite dirty.
- I removed the EGR connecting tube and cleaned it well; although it was not dirty.
- I cleaned the exhaust pipe, that connects to the EGR, as far as I could - it was not that dirty.

Every time I do something, I make sure that the battery is disconnected as to reset everything. I then connect the code reader and it says 'no codes'. After mixed driving of around 25 miles or so, the check engine CEL would appear and the code reader says P0401 (this latest time with an additional P0401 pending code).

Any ideas on how to get rid of the gremlins? Of course inspection and emissions are due at the end of the month.

 

[Dnj06ltd]

P0401

Have you replaced the DPFE also? Thats what reads the pressure before and after the EGR to see if it's actually opening or not. (Differential Pressure Feedback EGR) they'll go bad but the PCM thinks the EGR isn't opening correctly. Just a thought.

 

[suzook]

Have you replaced the DPFE also? Thats what reads the pressure before and after the EGR to see if it's actually opening or not. (Differential Pressure Feedback EGR) they'll go bad but the PCM thinks the EGR isn't opening correctly. Just a thought.

It's integrated on the egr on the 06's on up. At OP, check the wires that connect to the egr for any cracking, even under the wire tape and loom. These trucks have SERIOUS issues with brittle, and broken wires.

 

[08TXExplorer]

I thought I would post a solution to my issue. I finally gave up and took it in to be diagnosed. They said the DPFE was faulty! This is the second (after market) EGR that I had on it. So, I returned it and bought a Motorcraft EGR from Ford. Guess what? No more codes. All monitors have completed (none are incomplete). I so far have close to 100 miles with out issues.

I guess I learned my lesson (albeit an expensive one) on after market components vs OEM.

Thanks for all the suggestions and help.