Good evening, guys...I have a problem, that is perplexing...I have a 2000 F150 V8 4.6, I have been chasing a check engine light problem...it has been through the works. The first time my light came on, it was for the EGR valve, I replaced that, still didnt help. I ended up carrying it to Firestone, they took the intake apart and cleaned it good, still didnt help, so I had the catalyc converters changed out, no luck, I had a code for the oxygen sensors, I replaced the before and after oxygen sensors on the left side...a new code came up P0401, insufficient flow, so I replaced the DPFE sensor, truck drove 60 -70 miles no light, happy as hell, until I cranked it back up, the light is on again, I am having the code checked tomorrow to see what the hang it is now...Im at my ends with this light??

 

When I've had that code it was because the tubes leadin from the dpfe to the big egr tube were clogged. Take off the rubber vacuum hoses and ream them out see if that fixes it. Worked for me. use a hanger or a strong piece of wire.

 

will do, the DPFE looked pretty clogged up, thanks for the advice

 

In order to fix the code you have you will need to take the throttle body off, and clean the ports for the EGR valve.
They could look like this.. unless they cleaned them like you said they did. I had mine "cleaned" and they missed those too.

You want this

ALSO. If you got ANY other kind of DPFE sensor other than the motocraft sensor from the dealer then you have wasted your money. Any other brand is garbage. You also need to make sure that the tubes are on correctly, having them backwards will make the computer read the voltages and what not backwards which can cause problems as well.

 

Wow, it's difficult to answer the poster without possibly insulting him.
1. What code told you it was the EGR valve?
2. What code told you to change the the convertors?
3. What code told you to change the OX sensors?
Bottom line is you spent a lot of money on these parts that you didn't need.
Indeed you mis interpeted the codes.
The EGR system has a number of parts and involves several codes depending on what the PCM TEST was doing that resulted in a failure.
List the codes you now have and we will go from there and begin to explain what is going on in the tests that failed and what to test out.
It's much more complex than you are thinking. The codes don't tell you what parts to change 99% of the time, only what subsystrem you must deal with.
Glad my doctor don't replace parts on me when I feel bum, without knowing what i need.

 

True that! He did mention 401 though which is reason enough for me to believe he might have gotten a crappy dpfe sensor/switched the tubes/ or that throttle body needs a clean out.

 

I know that there's a lot of love on this board for buying nothing but motorcraft, but in the case of DFPE sensors, the original ones are known to fail. I've had the cheapest, knockoff DFPE sensor on my truck since I've bought it with no problems whatsoever. My thought process was that since the OE sensor was crap, hopefully the aftermarket would address the design flaw and make a better one. My cheap sensor may fail tomorrow, but for me, it's fine. YMMV.

A code for insufficient EGR flow is caused by either a problem with the EGR circuit, or the EGR flow sensor. The EGR valves rarely fail, but both the sensors and rubber hoses go bad, and the EGR ports get clogged up with carbon. Either or both will cause a check engine light.

One easy way to check that the EGR system is working is to start up the truck and let it idle. Remove the vacuum hose from the top of the EGR valve, and put another hose on it. Manually pull a vacuum on the EGR valve. If the EGR valve holds vacuum, AND the engine runs like crap or stalls out, then the EGR valve and system are good and you have a sensor problem. If the engine still runs good, then you truly don't have EGR flow, and there's a blockage somewhere.

The first place to look is the intake elbow that was mentioned above. Other places to look are the EGR valve itself can get carbon'd up, and the orifice tube itself (the metal tube coming up from the exhaust with the 2 rubber lines attached to it) can get plugged up.

If you pull vacuum on the EGR valve and the engine does run rough or stall, then the EGR system is working, and you have a problem with 1) the DFPE sensor itself, 2) the rubber hoses that attach to it, or 3) the wiring to the sensor.

 

Alot of very good info, however, I tried two different brand of DPFE sensor that went bad. One of them went bad as I was leaving the parking lot of the place that I bought it. The readings were perfect till I started driving, and then they shot through the roof. My original DPFE sensor was good to me for almost 160k, so I figured I would go back to the expensive Motocraft and try my luck again. Here I am at almost 175k now, and its been working great. I am not trying to have a pissing match with you or anything, all that I am saying is that I have had better success with the manufacture suggested parts made for my truck.