Here it goes.

2001 F150, 2wd, 4.6L,

Error code P0402 "Exhaust gas recirculating flow excessive detected"

I'm thinking this can only mean the EGR system. I replaced the EGR valve and the pooter threw the same code. So that's not it. I checked the vacuum control module (selenoid) for the EGR valve and it rang out with 34 ohms (book says it should be between 30-70), and read 12.49 v with the ignition on. Both readings were as they should be, so I'm thinking the vacuum selenoid is OK. I've heard that the O2 sensors can cause this code, but I'm not sure of that. My book says nothing about the small sensor in the EGR pipe (about midpipe between EGR valve and manifold) coming from the driver side manifold, so I have no idea how to check that. What do you guys think, where should I look next, and how do I test it?

The truck isn't running that bad, but it does have a pretty good stumble when it's cold, and may even rear it's ugly head when warm in another stumble or two. I do have a superchips tuner, so I retrieve my own codes and reset them to see if it throws it again. I have not taken it to a professional diagnostics yet, but that may be in my near future. I'm now leaning towards the problem being in one or more of the 4 O2 sensors, but that is just a guess.

Can anyone shed some light on this? Most common reason for this type of error code? I would REALLY appreciate any feedback you guys may have to offer. Thanks.

Nick

 

P0402 indicates that the EGR is open at idle. If your engine idles smoothly, then your EGR is obviously okay.

99% chance that it is a defective differential pressure sensor . . . very common.

 

Is that the little doo-dad that is mounted down about midway between the EGR valve and the exhaust manifold? If memory serves it has a couple of small hardpipes going to it right off the EGR hard pipe. It's connected to these small pipes via rubber hoses. The sensor itself is only about 1 1/4 square and maybe 3/8" thick. It's black and has a grey electrical connector on it. Is this the "doo-dad" you're talking about??? I kinda hope so....cuz that little sucker looks cheap...much cheaper than throwing $200 worth of O2 sensors on it!

Thanks for the responce,

Nick

 

I looked at the DFPE sensor in the book and can't find anything on my motor that resembles it, much less where the pictures show it to be location wise. The book has it, but the emissions diagram on the front of the engine compartment doesn't show a DFPE either. Is it possible that my engine doesn't have one, maybe only on Expeditions or sumthin? Or is that little monkey I described above, it. In my piece of crap book, the "doo-dad" I described above is nowhere to be found, it shows the DPFE sensor of course, but they look nothing alike and the sensor I described appears to be a 1/8th of the size of the DPFE sensor in the book. Arrgh.


Thanks

Nick

 

Sounds like it.

 

Thanks Stan....off the top of your head do you know how to test it. Ohms range and ignition voltage would be pretty damn cool to know. Or I guess if it's cheap enough I'm not above throwing parts at a problem hehe. I suppose I could use the test data from my manual, but the sensor I'm talking about looks absolutely nothing like what they show in the shop manual.


I really do appreciate the help Stan. Thanks

Nick

 

Recall# 02M01 All these vehicles have an additional 2 years and 24,000 miles coverage from original in service warranty start date.
2000 - 2002 3.0L 4V Taurus/Sable
2001 - 2002 2.0L (Zetec) Escape
2001 - 2002 2.5L Cougar
2001 - 2002 3.0L 2V (OHV & FFV) Taurus/Sable*
2001 - 2002 3.8L Mustang
2001 - 2002 4.2L F-Series
2001 - 2002 4.2L Econoline
2001 - 2002 4.6L Crown Vic/Grand Marquis
2001 - 2002 4.6L Town Car
2001 - 2002 2.0L (Zetec) Focus* (See Note)
2001 - 2002 3.0L 4V Escape*
2001 - 2002 3.8L Windstar*
2001 - 2002 4.0L Ranger*
2001 - 2002 4.0L Explorer Sport*
2001 - 2002 4.0L Explorer Sport Trac*
2002 4.0L Explorer/Mountaineer
2001 Explorer Stripped Postal Chassis*
2001 - 2002 4.6L F-Series*
2002 - 2003 4.6L Explorer/Mountaineer
2001 - 2002 4.6L Expedition*
2001 - 2002 4.6L Econoline*

 

Talked to a mechanic and he mentioned that I can put my Mighty Vac on my EGR valve at an idle. If the truck dies then it's probably the DPFE sensor (which I purchased one of them doo dads today =/ ). If it doesn't die and keeps on idleing then I'll probably have to pull the intake and clean it out because there would be deposits in it causing the trouble code to be thrown. But logically I'd think if this were the case then it would throw a "insufficient exhaust gas recirculating" code out, which I think is # P0401. I could be wrong on this...not sure. So I'll check the EGR at idle and see what happens there. I'll also install the new DPFE sensor and see if that cures it. Just an update, thanks for your help guys and I'll let you know what I find out. If anyone wants to add anything I might try then I'm all ears!


Thanks,

Nick

 

The DPFE sensor is going to be tied in to EGR tube by two rubber hoses,one slightly larger than the other.I have a small fleet of 02 Crown vics that I was getting either/ or EGR insufficient/excessive flow detected codes from and it turned out to be faulty DPFE sensors on all.Pretty common problem in police fleets.