How to: - Diagnosing DPFE Sensor (P0401 and P0402) with Scan Tool | Page 2 | Ford Explorer Forums - Serious Explorations

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How to: Diagnosing DPFE Sensor (P0401 and P0402) with Scan Tool

Prefix for threads which are instructional.
Do I have a DPFE sensor on my 01ST? and should I drain it? If so how?
 



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Were these on the 1st Gen 'X's? '91?
 






Were these on the 1st Gen 'X's? '91?

No, the early nineties had a linear sensor on top of the EGR valve. In my 20 years with Ford I don't recall having DPFE problems until late 90's, then it seemed like a flood gate opened. Whatever caused them to fail, 99% of the time an egr code pops up it is the sensor. Regardless of what AZ or the others try to sell you.

In my long career I have not replace an egr valve since the late eighties..............
 






Someone here is bound to bring up the fact of plugged egr ports on Ford engines, and that is a distinct possibilty on many, although rarer than the sensor problem, and usually on moderate to high mileage engines.

When diagnosing codes I always rely on what the data can tell me, not just the code. Codes are only a starting point, not the answer to the problem.
 






No, the early nineties had a linear sensor on top of the EGR valve. In my 20 years with Ford I don't recall having DPFE problems until late 90's, then it seemed like a flood gate opened. Whatever caused them to fail, 99% of the time an egr code pops up it is the sensor. Regardless of what AZ or the others try to sell you.

In my long career I have not replace an egr valve since the late eighties..............


Thanks. No current issues, just trying to educate myself for future issues.
 






What else?

I've been reading the earlier posts on this subject. I have already replaced the DPFE in my 2001 Ranger. I still get the dual P0401/P0402 check engine codes. What else can it be? Someone suggested that it might be the catalytic converter or the O2 sensors. Any suggestions? Thanks

2001Ranger
 












thanks

Hi, thanks for the welcome and the suggestion. I R&R the EGR and flushed/cleaned the valve, vacuum hoses, and exhaust tube? with carb cleaner and dried it out. I reset the check engine light and after the 3 starts it came right back on. Any more ideas? thanks. 2001Ranger
 






Hey I just put in a new engine and used all my old sensors. The old engine had a mega blown head gasket. I now have codes for my DPFE. Gee do you think that the blown head gasket could have introduced a little bit of moisture? Thanks for the good info!! :thumbsup: :D
 






2 Questions

New member. Glad to be here. I have a few questions...

1. Where is the DPFE sensor located on a 97 Explorer 5.0? Can't find it for the life of me! I have a bad feeling I have to pull the intake to get to it, though...

2. After I change the DPFE, how long do I have to drive before it resets? If I reset the code manually, how long before the P1000 clears out?

Thank you!
 






I got a 33 code code in my 1992 Explorer. I have the first slow 1-1-1 and then a faster 1-1-1 code ..a wait and it repeat the slow 1-1-1 and repaeat the faster 1-1-1. So thats why i think i have a 33 code. It give me a EGR code but where is located the EGR on a 1992 4.0 OHV..i dont see it. Thank you.
 






dpfe

SO... how does one swap out the old sensor for a new one when the plugs seem to be differently shapped? New plug is ovalish where as new one is not... explain?
 












Dpfe

No the plug in the picture on napa is OVAL shaped where as the old one looks like it's different shaped? Have you changed on of these from an original OEM part to a new OEM spec'd aftermarket?
 






'97 Merc Mount | 5.0L V6 | AWD

I just got the P0402 code @ 199,300.
 






sounds like you have a different DPFE than the original. I swapped mine out on my 2002 sport about three years ago after receiving a CEL. I bought a Ford DPFE to replace. No worries.
 






Gen 1

My explorer is Gen 1... any difference in the old sensor versus the new plastic one though?
 






Likley...

I checked my Haynes repair manual and it indicates two different pressure feedback EGR systems implemented on Explorers. The manual states "All 1995 and earlier models and 1996 5.0L V8 models are equipped with the Pressure Feedback Exhaust Gas Recirculation (PFE) system." And it goes onto say "1996 and later models (except 1996 5.0L V8 engine) are equipped with the Differential Pressure Feedback EGR (DPFE) system.".

The manual shows two diagrams of the feedback systems and the block diagram for the older (i.e., pre-1996) shows the PFE valve only having one orifice to monitor pressure. The diagram for the newer DPFE system shows the valve having two orifices to monitor pressure.

If this information is accurate, then to answer your question, I would hazard a guess the old (PFE) and new (DPFE) sensors are different. Do you have the old and the new plastic sensor available to look at? Are they different?

I know there are smarter guys on this forum that have hands-on experience with these systems. My experience is only with the new DPFE on my 2002 Sport (also replaced it on my 2001 Focus).

Good luck.
 



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Mine also has two lines into it...so confused.
 






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