1998 Expedition Diagnostic code P0401 Insufficient EGR Flow
#17
09-12-2005, 10:00 AM
#18
12-06-2009, 12:34 PM
DPFE Sensor
2000 Expedition 2WD-V8/4.6L I had the same code and when i went to change my DPFE Sensor it was not there and there were no loose vacuum lines or plugs. No evidence of it being there. Where do these vacuum lines and plug that connect to the DPFE Sensor come from? And do i really need it?
#19
04-04-2010, 07:04 AM
2000 Expedition 4.6
HELP!!!!!!!!!!!!!!!!!!!!!!!!
I have also been fighting this code problem:
Replaced:
EGR Valve, DPFE sensor, Solenoid, EGR Tube to Exhaust <NOBR style="FONT-FAMILY: verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif; COLOR: darkgreen; FONT-SIZE: 100%; FONT-WEIGHT: normal" id=itxt_nobr_24_0>Manifold
</NOBR>Recently noticed that I had 2 broken studs at the exhaust manifold...Replaced exhaust manifold all new gasket, studs and double male connector for EGR tube to go in to the exhaust manifold
Reset and drove for about 30-45mins before the S.O.B light came on again.
Now I did get most of these parts from Autozone which I've heard have a high electrical part fail rate.
Before I take it to the Mech. what else can I look for?
Thanks in advance
#20
04-04-2010, 07:47 AM
I had the low flow code pop up and it ended up being a bad vacuum line. Trace your lines all the way back from the EGR to the vacuum source at the intake manifold (not the ones going to the exhaust manifold from the DPFE). It will likely go through some trees and tees etc. I had a bad hard plastic line behind my alternator that caused it to throw that code.
#22
02-20-2016, 08:24 PM
same vehicle and the same problem...I have replaced the EGR valve, and DPFE sensor. Still the same code (p0401) 24 hrs later. When the engine is cold it will not idle high enough to run, I have to manually give it gas to warm up. I assume this is related but don’t know as no code other then p0401 shows up. Even if I disconnect the EGR vacuum it wont idle. The theory being that the vacuum is opening the EGR causing it to low idle...not the case. I have read about the ports being clogged, but that would be the same as the EGR being closed...again, that shouldnt cause the low idle. Only when the EGR is open will the engine idle too low...right? What else could the problem be? Im at the end of my rope.
I had rough idle, almost like a loping kinda sound, and it would occasionally die if my foot wasn't near the gas.
This has happened to me twice now with the result being the same , once the O2 wire was munched between the tranny and the engine when I had it worked on at a shop, frying the computer, making it run dirty, eventually breaking a valve spring, losing half of the retainer, and bending a valve right near the valve head . The second time being because my O2 s went out from all that dirty exhaust , killed em, making it go to limp in mode and lope every once in a while, and ultimately losing compression in two cylinders from the valve guides, also lost some retainers this time.
So I'd check your computer, O2 sensors, make sure you don't have any damaged valves, and think about your catalytic converters once Ina while, if it's a 99 chances are it may be ruining your exhaust flow. Hope something In this clusterbomb of words can lead you in the right direction ! 👍🏽
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