Bernard,
The DPFE-3 sensor you are referring to should look like this and is more commonly known as an EP(Exhaust Pressure) or EBP (Exhaust Back Pressure) sensor.. It's located here (pic10 / #3 ) right?

Sounds like the EBP code has gone away.. P0401 can be caused by many other things besides a bad EGR valve, and can be difficult to diagnose... The way the PCM proves EGR flow is by either detecting a rise in temp from sensor IAT2 when the valve opens, or by changes in EB, MAF, and/or MAPduring EGR valve actuation.. The logic it uses is determined by your PCM programming(flash)..

P0401 can be thrown because of a dirty IAT2 sensor or very small induction or exhaust leaks.. These problems can be difficult to diagnose.. Since you've already changed the EGR valve out, you've eliminated the most obvious culprit.. Before you spend any more money on parts check to make sure all your induction connections are clean and tight.. There is the intake side to the turbo, and 4 boots between the turbo and intake elbow.. The hot side turbo boot sees a lot of abuse during normal operation.. The hot side innercooler boot(pass side) is prone to developing a split or tear on the bottom side.. It may look like it's leaking oil as CCV oil can build up there..

Once you're sure all of these connections are good, check for exhaust leaks... Up-pipes are prone to developing leaks and soot on the firewall is a way to tell if they're a problem..

Last easy thing to check is the IAT2 sensor on top of the intake manifold (pic 18/ #4).. If it looks dirty you can try cleaning it with MAF cleaner.. I guess while you're digging, cleaning the MAP tube wouldn't hurt either.. The sensor is mounted on a bracket next to the A/C evaporator box at the rear of the engine compartment/passenger side... Here's what the sensor looks like... You can trace the tube back to a port on the intake manifold..

If you still can't find anything, it might be time for a pro to look at it.. Me personally, I throw P0401 every once in a while and I don't worry about it..I can scan while i'm driving and clear it when I stop again.. I've dealt with it for over 3 years now.. If I don't have any drive-ability issues, it's a nuisance code AFAIC.. The dealer will want to reflash the truck if I take it to them, and i'm happy with what I have now..

 

Dan, thanks for roadmap. Looks like I have a lot of work to do.
Take Care, Bernard.

 

William,

First Thanks.

Yes, I changed the EBT (Motorcraft lable DPFE-3 4C3Z-9J460-A).

I will check and clean the IAT2 sensor and Map tube tomorrow.
I will also check the intake (turbo) and exhaust.

I am ordering a AutoEnginuity scan tool tomorrow and will do a KOEO test on it as soon as I get it.

If that doesn't work, I will tear down the engine when I get back from vacation. I want to change the head bolts, and clean or replace the egr cooler. I live in California and need to keep it CA emission legal.

I am going to have to join as a supporter so I can post pictures.

Brick Wall refers to "Last Lecture" by Randy Pausch.

Once again thanks for the help, take care Bernard