P0401 EGR Flow Insufficient

So I've gathered from all the posts I've read that very likely we really need to change the DPFE Sensor. Should we just go straight to that, and see if we can get the code to stay away, or should we do something with the EGR Valve itself, like clean it?

We're going to be changing our front brakes this weekend, so might as well throw in another project, too. If this weren't done before we go out of town next week, will it cause any problems, other than maybe bad gas mileage?

Thanks for all the wonderful help I've found here!

You didn't mentipn the year but the DPFE is a common problem for some years. On my 99 for example, the part has been redesigned and the new style is in a black plastic case and not the problematic version in the metal case.

I outlined a test procedure a while ago. You can search under DPFE and do the simple test or for about $60-80 and 15 minutes of your time simply replace it.

The purpose of the EGR valve is to add some of the exhaust gases to the intake stream. This causes a reduction in the combustion temperature and thus reduces NOx emissions.

Of course the EGR could be functioning properly and just the feedback is incorrect. I left mine for about 2 months before correcting it.

A DPFE causes not driveablity issues other than maybe a tenth of a gallon a mile. I would go straight to the DPFE no questions asked, as that is what Ford tells us to do. After replacing the DPFE, if the problem persists we're to diagnose the EGR valve, but to be honest I couldn't tell you how to do that without looking it up, because I've never had the problem persist. Good luck with it, it's a five minute job and saves you the EEC diag at the dealer!

if you have a vacuum gauge you can hook it up to the EGR hose and check if it really is working. On Fords you have to drive to check it, it won't usually work in park or in drive with the brake on even if you rev it, you gotta drive it.

if it's got vacuum, then actuate the EGR by pressing up on the valve or by applying vacuum. Do this at idle. If it stalls, it's working.

If those two tests pass ... change the DPFE. If they don't pass, don't change the DPFE, because if the EGR ain't workin' the DPFE ain't readin' nuthin'.

Thanks for the help so far!

We're pretty much novices here. Where do we get a vacuum gauge, and how would we hook it up to do the test? I guess it may say in the Haynes manual, but after doing the brakes this weekend, we've found that this particular Haynes book is rather vague. LOL But is the vacuum gauge something that AutoZone or Advance Auto would loan out?

Oh, and it's a 2001 with somewhere around 75,000 miles on it.

i know kragens loans stuff for free ... i guess autozone too? a vacuum gauge isn't too expensive, so i imagine they would loan them. they are easy to use, just connect it to the hose, if it's sucks then it will read read vacuum, if it isn't sucking, then the needle won't move!

Our Haynes manual only has pictures for the 3.0L engine and it doesn't correlate well with our 3.8L engine. Do you know where we could find better pictures to change the DPFE sensor? Got one from the dealer for $32, but can't find it in my car.

OK - on the off-chance that anyone is on tonight, how do we get the thing off?? We did manage to find it, right smack in front of us, but the new part is bigger, so that was throwing us off. We got the wire off, but how do we get the prong parts out of the tubes they're in (real technical language, I know!)? Haynes says something about a bolt or screw, but there's nothing there, other than the little plastic screw holding the wire in place, which we have removed. We have both been pulling on it pretty hard, and it's not budging. Do we just pull really hard, and eventually it will come out?

If you are refering to the hoses that lead to the EGR tube then yes pull and twist at the same time. You could try a bit of WD40 but you may have trouble getting a proper seal on the new one so that should be a last resort.

Ensure that you mark them as they are different inner diameters and they need to go on the correct tubes on the new one.

Thanks everyone! We did finally get it off last night, just lots of pulling and twisting, like DRW1000 said. Started it up this morning, and the CEL is off, didn't even have to get it reset. Looks like that did it!