I have a 2001 ford f-150,4.6 liter.i keep getting a po401 code.I've cleaned the egr passages in the throttle body replaced the dpfe sensor and checked the egr valve.I don't have a vacume tester but i sucked on the valve and it's not stuck or dosen't leak down for as long as i can hold my breath.any suggestions would be appreciatted.

 

What r you doing with that thing ???

Someone tell you to do that ? - That was mean lol .

 

This is how it goes when the problem is not the simple quick fix.
There is more to this than what you worked with.
How about the vacuum regulator solenoid that operats the EGR., the vacuum lines?
Did you use a Ford DPFE replacement?
What condition is the manifold tube in?
Is the calibrated orfice in that tube, open?
Is the tube solid with no rust thru or cracked.
The operation of the system has several phases from cold start to tests while hot running.
A problem in any part will not pass an internal diagnostic and produce a failure.
The PCM does it's first test at cold startup and drive away for pressure checks.
Hot run checks involve the PCM comanding about an 80% opening of the EGR then using the DPFE to measure the pressure drop accross the main tube orfice for a pass or fail.
So you can see the many places that can cause a problem.
The hot check must fail two times in sequence to set a falure code.
Good luck with it.

 

There is a vacuum actuator that has to send vacuum to the valve to open it. Every other component could be functioning but if it is not sending vacuum to the valve it will not open. The EGR valve could also be stuck shut. Both of these could cause your P0401 code, Insufficient flow. Obstruction in the hoses going to the DPFE could also cause the code.

 

Did you see that? Blue grass and I posted at the same time but his got to the server first.

Regards

Jean Marc Chartier

 

i've got vacum on the egr under a load.The egr valve is working when i pull it off and suck on it.The lines going to the dpfe sensor are not clogged or cracked.I bought the replacement dpfe sensor at orielys it is not a ford part it's a BWD brand.I found a couple of vacum leaks and repaired them and reset the light.

 

What does this mean lol?

Okay, but how did you determine this? To determine, you have to do this @ idle and listen for deflection. Is that what you did?

Okay, but why didn't you repair the lines first, -then reset the light before replacing the DPFE Sensor? Why purchase third party when theres a good chance it's defective? This is a dealership ONLY part on your model.

 

i didn't know the aftermarket part wasn't a reliable part,live and learn i guess,and as far as the vacum leaks, i just didn't find them at the time.So far the light hasn't come back on.I drove the truck for about 15 or 20 miles.I'm keeping my fingers crossed.

 

Yea, your going to need,- most likley 3 or 4 drive cycles behind you to know for sure - Depending on the cycles.

If you get the light and the DTC again, I would re-install your old sensor and try again, since you found leaks.

 

it came back on on the way to work this morning. i reset it and put the old sensor back on.

 

Did you suck test the EGR valve properly? I know you did something there, but did the engine idle go all goofy and almost die when you did this?

 

I just pulled the egr off and sucked on it with my mouth to make sureit wasn't stuck.I don't have a vacum tester.i plan on tinkering with it some more friday.i was tired when i got home this evening and didn't feel like fooling with it.

 

Dont screw around with after market DPFE sensors. When I changed mine, went to Autozone, and they wanted $80 for it. Checked the Ford dealer here in NE Ohio, and they wanted $36 for it. Its a no brainer. Always check dealer prices against parts stores, because sometimes part stores are the one ripping you off.

 

That's not what I asked lol - You don't need the tool, you gotta suck. Maybe I better put this another way.?

Well just do it while the motors running and post what happens, when you get around to it