Ive got a 2002 Explorer EB, 4.6, 71k miles. A few months ago I got the "service engine soon" light. I looked into the issue here and elsewhere, found that the DPFE sensor is a usual problem. So, I picked up a new one, installed it, also disconnected the battery to clear the light. Issue solved. Great. So a couple weeks go by, the light comes back on. I pulled the sensor again and it had alot of moisture in it. Shook it out, reinstalled it, the light went back off again. A week or so later, the light came back on again, I removed the sensor again, shook the water out of it again, reinstalled it, the light went back off for a few days, its now back on again. So, it looks like I have another issue. Why does it keep getting fouled with water/moisture? I tested the EGR valve, it works correctly. I did not test the EVR, but i did remove it and inspect it. Looked fine. The truck runs fine, but it does have an annoying "shhhh" noise you can hear at certain times when driving the car that seems to be coming from the engine area. Can the EGR tube go bad? I also disconnected the EGR line and plugged it to rule it out because i thought the EGR was running wide open alot (bad EVR) and that "shhhh" noise was the exaust rushing through the EGR tube, same noise and same moisture. I did not pull any codes and dont have a reader. Autozone checked it and only responded with "you need to take it in to the dealer". I just put $1400 in the rear end of this thing. Im not taking it back to the dealer. My next guess is the EVR.

Matt

 

You need to pull the codes.

 

Moisture/water vapor our the tailpipe is normal, just not excessive amounts.

are you using any coolant?

 

No, not using any coolant. For some reason too much water is making its way up to the dpfe. Im gonna do a bunch of checks tonight.

 

Are all your runs of short duration?

 

No, I have a 20 mile each way drive to work each day. I see what youre saying that maybe the short runs wouldnt get it up to temp to burn off the moisture, and I agree. But, i dont think thats happening here. Im going out in a few minutes to give this thing a good look over and test the EGR again and the EVR. I may pull the TB and look at those passages everyone talks about getting all carboned up.

 

What about burning ethanal fuel combined with parking in a garage and then suddenly hit the cold air....?

 

Moisture in the DPFE is normal.

Are you pulling the codes each time? If so is it always the P0401? Or are you just guessing that's the problem, because a lot of things can set off the engine light...

 

I wasnt guessing, I was trying to use some thought to diagnose it. As mentioned above I havent pulled any codes, but its looking like i need to find a reader and do that. Mazda guy, you may be right. I was assuming the moisture was tripping the light but maybe I have another issue. I looked it all over last night and this EGR system looks ok.

Anyone know the answer to this. When testing an EVR off the vehicle, if you apply vacuum to the lower port, shoud it hold that vacuum? meaning when the solenoid energizes it lets the vacuum throught o the EGR valve? My lower port doesnt hold vacuum.

 

Seriously matt.. get your codes pulled before you worry any more about the EGR system. Go to a local autozone or any large auto parts chain store, they will usually pull the codes for free.

Then post what you have here and we'll do what we can to help.

 

Did you use a Ford DPFE?
The new ones have been updated and the water doesn't seem to bother them as much anymore.

 

I got the new DPFE from Autozone, It is plastic and has a vent on it. As mentioned above, I had Autozone try to pull the codes and he said something like "Its Ford proprietary, you will have to go to a dealer". The guy was an *** so maybe I nedd to hit a different Autozone. Ive been asking around work to see if someone has a code reader. Ill post again after I get some codes.

 

I had a P1400 code which is the DPFE sensor bought a new sensor from auto zone for $38 bucks worked fine for 2 days and then same code came back.
Long story short bought another sensor from local ford dealer and never got the code back yet. Parts guy at ford dealership said there was a couple revisions to that sensor, seems to be a common problem with that sensor

 

Im still waiting for the light to come back on. The other night when I looked it over I pulled the DPFE sensor and dried it out good, I also pulled the EGR valve and looked at it again. I noticed some flaky debris near the orfice so I cleaned that up good. I also pulled the EVR and checked it too. I washed the EVR filter, the EVR had some dust/sand in it so I knocked it out and then rinsed the topside out with WD-40, I also squirted it in the vacuum ports. Figuring I had nothing to lose and a new EVR is only $24. I shook all the excess WD out and reinstalled it. Reason I did that was I noticed that at idle the EGR vacuum line had a weird pulsating vacuum signal, it should have 0 in/hg or darn near it, manuals say less than 1. So I thought maybe the EVR was dirty or hanging up inside. So here I am 2 days later waiting for a service engine light to come on, nothing. It usually would come back on by now. If/when It comes back on I will get codes pulled. Also, the funny "shhh" noise I mentioned in my first post is gone....

 

If it comes back on take it back to autozone and have them scan it again. They use generic OBDII scanners that won't give a code desription if it's not a generic code, BUT it should still give the code number. At the very least have him tell you the code number and post it on here and I can look it up for you.

Good luck.