2001 Windstar P0401 EGR Insufficient Flow

[chasealley]

Hi all,

Owned my 2001 Windstar almost 3 years and this is the first time the CEL has come on.

I just finished some big maintenance early last month. Trans fluid, engine oil, cabin filter, fuel filter, rear brakes, fuel injector cleaner additive. We went on vacation, 1570 kms. On returning the van still only has about 110,000 kms on it. 3 weeks later....

While driving a short trip, a few blocks, we noticed the van shudder a little bit. I thought maybe something to do with the trans. It wasn't very noticeable but enough to cause the sensation of moving forward and back slightly. Sort of like experiencing a 4.5 earthquake that triggered 50 miles away while you are on top of a 4 story building. Enough to feel the sensation, but that's it.

Upon starting the car up again on our way home the CEL/MIL came on right away. Got home and ran my scan tool on it and here is what I got.

P0401 Exhaust Gas Recirculation Flow Insufficient Detected

Freeze frame data

Calculated Load: 32 %
Coolant Temperature: 178 F
Engine RPM: 1320 r/min
Fuel System Status Bank One: Closed Loop
Fuel System Status Bank Two: Not Reported
Long Term Fuel Trim Bank One: -1.56 %
Long Term Fuel Trim Bank Two: -0.78 %
Short Term Fuel Trim Bank One: -1.56 %
Short Term Fuel Trim Bank Two: -2.34 %
Vehicle Speed: 28 MPH

Anyone seen this before? Could this be related to a vacuum issue? I had the top intake apart a year ago and the EGR ports seemed ok, maybe a little clogging.

[northern piper]

I bet it's your DPFE. Do a search, lots of them go bad and usually throw a 401 IIRC.

Piper

[Andrew1941]

I have the same van 2001, same code, same shudder and 125,000 km. I haven't found the problem yet, nor have I spent much time looking yet. It can be numerous things with the DPFE (air flow sensor) just being one of them. It can be the EGR valve is not opening or closing correctly, the vacuum line to the valve could have a leak (probably the rubber elbow off the top of the valve back to the EGR is loose and you can spin it easily..if so, there will be a leak there causing some if not all the problem), it can be the solenoid valve on the vacuum line at the back of the EGR not functioning correctly, it can the computer that tells the solenoid to open not sending the correct signal, it can be a fault in the wiring and I am sure I probably missed a few others. In general, you are on the right track. I had fairly heavy shuddering between 1500 and 1800 RPM on slight uphill only. It seemed like a shifting issue, but it wasn't. It was the rubber 90 degree boot at the top of the EGR valve was leaking between the valve and the boot. Over time the rubber seems to expand making the connection loose. Mine had an oil deposit all over the top of the EGR valve. I had always wondered what was causing the oil build up until I found that issue. I believe it was caused by oil vapour being pulled up the vacuum line when the engine was running and then when off, it would run by gravity back down the line and leak out the connection. I tried to get a new elbow, but Ford wants you to buy a bunch of parts you don't need, so I took a zap strap and tied it around the rubber and pulled it tight. Then I removed the elbow from the valve, pulled the strap a little tighter and then push it back on so it was a snugg fit. Seems to have worked fine as far as clearing up the shudder (about 99% better with only the odd shudder , but significantly less); however, the P401 code is still persistent. I just want to figure out how to test the DPFE before I buy a new one and/or how to test the EGR valve? I got a feeling my problem is one of the two buggers.

[chasealley]

Hi again,

Thanks for leading me down the EGR path. I looked in the repair manual and the old PC/ED technique was to run a KOER test and check for a particular code. Using my AutoEnginuity Scan Tool I ran the test, it threw the code, viola. The repair guide says that indicates a hard failure. Had the KOER test not thrown the code it would have indicated a vac line, plugged port, etc that really did cause the reduced flow. The repair manual had a whole bunch of pinpoint tests following a pattern that might be of use too Andrew. But for me I'm thinking a cleaning of most of the EGR components is in order, and probably replacement of the DPFE.

But I'm wondering how the system knows it is a hard failure? Not that it matters. But just in case, can these things be cleaned like the MAF sensor? The DPFE on my car is a plastic housing, and it is a ford part. It looks like the top can just be popped off there. Anyone have experience with this?

I'm going to see if I can crack it open tomorrow and see what the guts are like. If anything I'm hoping it is just some contamination that can be cleaered. Probably wishful thinking.

[wiswind]

Most common causes of this code are DPFE and clogged EGR ports.
There is a great right up here for your vehicle
http://leckemby.net/windstar/windstar01.html

The baffel in the front valve cover most likely does not apply to your 2001......I remember reading that FORD had corrected this by then.

To clean the EGR ports.....you have to remove the upper intake manifold (the black part) to get to them.
The website that I linked is a great resource which was posted by a member here.
It has some great pictures.....that show what is involved.

[Andrew1941]

What is a KOER test? and how do I do it? I have a simple code reader, i.e. I do not get all the info you got off yours, but it will give me the code thrown by the computer. My CEL is showing code P0401 for insufficient EGR air flow right now.

I really want to know how to narrow down what the problem is before I start buying parts and just guessing at it. There are a lot of possibilities with P0401. Any guidance would be appreciated.

Seems my van is starting to get bad again for the bucking. After fixing the loose hose at the EGR valve it has been good for about 6 weeks until this past weekend where it started bucking quite a bit again. Its really just a nusicance b/c the van runs fine and the mileage is good, but I want to get to the bottom of it. I already cleaned the the EGR system in the spring and changed out the gaskets so I don't beleive I have that as the problem. If I get really desperate, I might open her up again just to confirm the ports are clear, but I am not that depsarate yet.

[northern piper]

well all I can tell you is that a number of people I know with 2000 3.8 have done the 171/174 repair only to have the 401 code thrown at a later date. Most seem to be around 2-6 months after the 171/174 repair. Of those, including me, that got the 401, we hadn't replaced the dpfe before. Replacing the dpfe and clearing the code has resulted in zero codes since. That repair for me was Dec 2007. The dpfe is not serviceable. When you get the new one make sure it's black plastic, not the aluminum one.

I'd be bettin' the dpfe.

Piper

[Ed_Strong]

Originally Posted by Andrew1941

What is a KOER test? and how do I do it?

KOER = Key On Engine Running test

You need a specialized computer or diagnostic scanner to be able to perform this test. With the diagnostic scanner connected to the ALDL and the engine running at temp, you select the KOER test and the scanner does a diagnotic test on the main engine componets (turns fans on, revs engine while you move the steering and apply the brakes, measures input and output of O2 sensors, etc) and then gives you a rundown of any systems that are not performing to specs, malfunctioning or tells you if they pass. At least thats what my Snap-On Scanner does.
There's also a KOEO test that you can do...

KOEO = Key On Engine Off test

This one checks relay and electrical components for shorts, in or out of range readouts and such!

[northern piper]

Hey Ed, can you give us some info on your snap on scanner? I only have a simple Equus one and would love some more scanning "power". Whatcha got??

Piper

[Ed_Strong]

It's a Snap-On MT2500 Scan Tool like this one here http://cgi.ebay.com/ebaymotors/SNAP-...mZ190252061592

It's and oldie (mid to late '90s) but it can still be customized to analize and diagnose the latest cars it even works most of the new CAN system functions from what I hear. I've seen some bare used ones go for as little as $60 on ebay.

The pre 2003 cartridges are dirt cheap too so it helps for the Windstar owner who wants a decent diagnostic tool! But if you can get a Global OBDII Cartridge at a good deal you'll be able to cover just about every single OBDII car out there http://cgi.ebay.com/Snap-On-MT2500-S...d=p3286.c0.m14

The Tranny and ABS cartridges are still a little high but still affordable and not as high as the latest models floating around. I'm on a budget, so I haven't been able to afford them.

[Andrew1941]

Hey guys, I did some research into the EGR systems while trying to understand it all and make sense of the trouble I am having. I posted some links on page three of the thread "EGR Mystery". Go read those and you should have a much better understanding of what you are trying to figure out.

http://www.automotiveforums.com/vbul...=915813&page=3

[Andrew1941]

Last night I cleaned the vent on the solenoid, which really wasn't plugged and I tested the EGR valve (proved it works) and tested the DPFE sensor and proved that it didn't work. Replaced it and reset the CEL. Seems better, but I hate to say I fixed it until a while has passed. I will report back. Then I may post some pictures and details on what I did...

[Andrew1941]

All is good, no CEL, van works great. Hopefully it stays that way!

[northern piper]

so.... what'd I win 'cause I bet the dpfe????

Piper

[Andrew1941]

You were convincing enough that I almost did it just because you said so, but I decided that since you didn't tell me how to test the DPFE, you win nothing! Ha Ha.

I did figure out how to test the DPFE by doing a bunch of reading and now I am all that much wiser, so thanks for not telling me. I have already fixed my vehichle and someone else's too.