Last week my service engine light came on. Friend checked it with his code reader. Got a P0402 code insufficient flow EGR valve. I have read several different threads on this subject on another Ford truck forum, slightly confusing me. Should I trust the code and just replace the EGR valve or do a number of other things that I have listed below that have been suggested by others on the another forum.

1. Clean the throttle body first?
2. Test the EGR valve by blanking it off?
3. Test the DPFE valve?
4. Replace the DPFE valve instead of the ERG valve since the EGR valve rarely goes bad?
5. Only get OEM parts since after market parts do not last?

I plan on diving in on this problem on Thursday so some good guidance would be greatly appreciated.

 

Go look up the code definition again...

 

OK messed with it some yesterday evening, pulled both the egr and dfpe, tried to do some cleaning, really didn't have the right things needed, put it all back together, disconnected the battery, it cleared the code. Did OK until driving home this afternoon, ses light came back on. I will have my friend scan again and make sure I get the correct explanation for the code, sure the code was P)402, not sure about the explanation though.

Doing more reading in places and seems most say dfpe replacement is usually the fix. I am going to do some testing and better cleaning on both but at independently and at separate times to hopefully confirm my thoughts that the dfpe is the one to replace.

Always open for suggestions.

 

OK...my bad....I had the fault explanation right......insufficient flow detected......gave the wrong code ...it was PO401. I think I will clean the DPFE again and clear the code only to see in a short time the SES light return to affirm to replace the PDFE first, hoping that will correct the whole issue.

 

Looked online on the ford parts site and found two dpfe sensors listed for a 4.2 f150. One was 58 bucks, the other 108 bucks.

Has anyone ever substituted the dpfe sensors, put on the plastic one in place of the metal aluminum one?

Did some calling around about parts. I was told the difference between the two was the metal one ($108), which I have, was originally put on the 1999 f150 and half way through the production year they replaced it with the plastic one($58).

What is the difference other than material? Can they be interchangable? One dealer did not even carry the metal one and never heard of it. They only have the plastic one.

 

OK thought tonight I would do some work and try to see why I was able to have the ses light go off but for only a day so I was going to do a process of elimination on some cleaning. Figured I would start with the easier access of the 2 components to take off and that was the dpfe. took it off did some cleaning as best I could put it back on, disconnected the battery and reconnected and started the truck, low and behold the ses light was off. so I am thinking more and more that is the part I will be replacing. I am going to drive it until the warning appears again and then take it to advance to let them put their scanner on it to get the volts reading from the dpfe. this could also confirm the problem part. was going to do a seafoam cleaning but could not find an easy place to pour the chemical so that it might make it to the dpfe or erg so decided against messing with it, especially after cleaning the dpfe and the light going off.

Any input on the 2 different dpfe parts would be appreciated.

 

https://www.ford-trucks.com/forums/1...g-mistake.html

 

For information, it takes two drive cycles before the EGR system failure twice in sucession will set a code for 401 so you may still have an issue.
Adding any cleaner will never get to the DPFE or EGR because they are in an area outside the motor not accessed from inside the motor.
You already have worked on those areas and can see there would be no access by any cleaner.
The DPFE is connected to the exhaust system as is the EGR.
The flow is into the engine by exhaust pressure and intake vacuum so neither will benefit.
Good luck.

 

Bluegrass, I know the cleanings won't fix the problem. I was hoping by cleaning the parts would help me figure what part to replace by process of elimination.

Do you know if the plastic DPFE is interchangeable with the metal one on my truck?

 

Yes but use only the plastic type.
Good luck.

 

My 99 4.6 did exactly the same thing as yours. First do this hook a piece of hose to the EGR valve and with the truck running pull a vacuum on it, if you don't have a vacuum tester simply suck on the hose and the engine should stumble. If it does the EGR valve is good and that part of the EGR system is clean if not, pull off the throttle body and pull off the part that the valve attaches to and clean the crud out of it. If you have a metal dpfe sensor go ahead and replace with the plastic one.

 

I believe your light is going off, because the PCM resets the codes when the battery cable is off for more than ~10 minutes. I replaced my DPFE with the plastic one, with no change at all. I've also read that using ones that aren't Motorcraft will throw codes, so I guess I will see. The one I got was standardized for OEM, so I'm hoping it will work lol.

 

Did any symptoms coincide with the SES?

Check out this link.
Part 1 -How to Test the Ford EGR Valve and DPFE Sensor.


You will need a little multi meter found here....

Digital Multimeter - 7 Function, w/ Backlight

 

--- Only use the official Ford DPFE unit. There have been many comments on FTE about aftermarket DPFE's not working out correctly.
--- You've done lot of things, but you haven't reported the basic EGR valve test, which was already mentioned a couple of posts back. This must be done first when evaluating a P0401 code & has nothing to do with cleaning anything, or disconnecting the battery. Whenever you disconnect the battery you reset your code status anyway, regardless of what else you do.
--- I looked at this: Part 1 -How to Test the Ford EGR Valve and DPFE Sensor., and disagree with this part:
When my EGR valve went bad, I got a P0401 code, but had absolutely no other problems (outside of not being able to pass my state's emissions test). I wasted a lot of time & money cleaning & replacing things that didn't need it, when the only thing necessary was to replace my EGR valve, which was almost as easy as replacing a DPFE. The EGR valve was way cheaper than the DPFE, too.

 

My van is running perfectly but I have the 0401 code. I have replaced the EGR valve and the DPFE and related hoses that go to the DPFE. I am still getting the code. I used Motorcraft for the DPFE but O’Reilly’s for the EGR. Any tips anyone can give me would be welcome. I am late to register because I have to pass smog where I am in order to register. Also, my concern is it is something bigger/more expensive. What is the worst case scenario? Thanks!