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Old 07-08-2007
HRoc's Avatar
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Join Date: Jun 2006
Location: Southern NH
Posts: 144
What would cause problems with an EGR system?

I just had this whole thing replaced not even a month ago and it cost me $389 (4 hours of labor to remove the bottom end of an EGR valve tube). And since then it's had a check engine light problem.

Now I thought it was the 02 Sensor but it turns out it wasn't so I returned the Bosch sensor I bought and had the Check Engine light re-tested using a hand held OBD II scanner both over at Autozone and Advance Auto.

Pulled a code P0401 which was for the EGR system.

I don't get it these parts are brand new: The EGR valve from AutoZone and the EGR tube from a local Ford Dealer.

And now it's giving me problems?!

Heres the problem as listed by Autzone:

EGR system fault (Exhaust Gas Recirculation) explanation.

The ECM has detected too little flow on the EGR system

Probable causes

1. - Blocked passage on EGR system
2. - Failed EGR valve
3. - EGR Solenoid faulty
4. - Failed EGR pressure sensor where applicable
5 - Failed EGR position sensor where applicable

Now here's another weird part, where the bottom part of the EGR tube bolts up to the cast iron exhaust manifold, I saw that the place that worked on my truck didn't use the supplied bolt that came with the new EGR tube..instead they use a bolt and two washers to secure it in place.

Would that cause the ECM to go haywire? I have the OEM bolt that came with the new tube sitting on my t.v set in my bedroom, and it's making me think if that's the ultimate root of the problem.

Any ideas?


I guess what I failed to ask was ; what would cause the ultimate problem for this premature failure..I mean these parts are brand new but it just baffles me that it's doing this.

Last edited by HRoc; 07-08-2007 at 01:18 AM.
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Old 07-09-2007
Join Date: Nov 2005
Location: Elizabeth City, NC
Posts: 767
Well, quite simply, P0401 usually means the DPFE sensor is bad.

That isn't one of the parts you just replaced, and it is a common failure item.

I suppose that fitting could be leaking, for which you should take it back where you got the work done. That could be why the DPFE is reporting low flow. Doing its job.

Last edited by Earl43P; 07-09-2007 at 07:52 PM.
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Old 07-09-2007
67cobain94's Avatar
Join Date: Jul 2005
Location: Vero Beach, Florida
Posts: 708
I agree with Earl. It sounds like a DPFE sensor and like it was misdiagnosed.
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Old 07-11-2007
NastyNate's Avatar
Join Date: Oct 2006
Location: Vacaville, CA
Posts: 92
I dont have a check engine light but i think i am having the same symptoms that would cause a bad egr valve... My revs seem to breath alot.. when i am in neutrual my revs will stay where they which might be at like 3-5 thousand. and or they will raise for about 10 seconds and then drop to "normal" status.... if you can make sense out of that .. no check engine light.
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Old 07-11-2007
Join Date: Nov 2005
Location: Elizabeth City, NC
Posts: 767
Search "IAC" for that symptom yet Nate? Read up.

Got any vacuum leaks? Search on "high or fast idle". You need to be more descriptive.
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