I've been searching and reading threads for the past 45 minutes and I'm thinking that since tomorrow is Friday, I will go ahead and buy a DPFE sensor at the dealer and then troubleshoot this EGR flow insufficient issue over the weekend.

Since my Expy has over 150k miles and the soot buildup appears to be a given and I've never cleaned out the ports, I think this is probably my problem.

But since the DPFE is also prone to failure, I'll have the part if that turns out to be the problem.

I'll start with the simple test described by applying a vacuum to the EGR valve with the engine idling and see if the valve functions.

But here's my question, that I haven't been able to find. Probably because it's such a dumb question to ask, but what the heck, I don't care if I make a fool of myself.

What is the throttlebody and where is it? Is it under the EGR valve? I've found pictures that others have posted here regarding the DPFE replacement, but they didn't identify the TB.

After reading what's involved in cleaning the throttlebody, I'd like to attempt this myself. Afterall, I've successfully changed the plugs on my '97 Expy 4.6 2 times now, so I know if I can do that, I can do this. Once when it needed it, and the second time when the heater hose leaked on #3 and #4.

And I've searched on both P0401 and throttlebody and found lots of descriptions, but no real clarifying answer.

Thanks in advance.

 

I just had the same fault code on my wifes 03 exploder and by following the pinpoint tests in the manual it lead me to replace the dpfe sensor. The test on it had me check the voltage at the sensor w/engine off key on, if the voltage was between 4 and 6 volts dc to then just change the sensor. The easiest way to locate the throttle body is to look at where the duct from the air filter goes to, it will have a butterfly in the opening that is prone to gunking up where the the butterfly seats. They make a specific cleaner for the job of cleaning this area. Hope that helps.

 

Could these alone cause the P0401? (see picture below) These are the white vac lines behind the battery near the firewall that others said to inspect and make sure they weren't broken. I have 3 breaksright at the black coupler things?

I applied the suck a milkshake through the EGR Valve and sure enough, the car started to stall out, so my ports must NOT be clogged.

I bought the replacement DPFE sensor, but at $165.00, if it's just these 2 lines, I'd rather just return the DPFE to the dealer on Tuesday.

If I open the bag, it's mine.




PIC - > IMAGE DUMP

Another question regarding the picture, the breaks occured at what to be couplers? I can just bypass these couplers right? Autozone sells replacement 1/8 hose, but because of where the break is, I would just bypass the black portion. Sorry about the fuzziness of the pic.

 

It can't hurt to try just repairing the lines and then reset the code and see if it returns. I don't see any reason you can't bypass the the couplers as long as they are connected to the correct port.

 

Thanks for the quick reply. I'm going to try that and see what happens. The coupler assembly also has some rot, so I'm going to try and bypass it altogther. I don't think I can get the lines mixed up. Larger diameter black to black. Smaller diameter black dead ends, tan to tan, and white to white. I wonder what corroded them. Appears to be some black substance.

 

Since you guys freely share your knowledge, I thought I'd give something back.

I'm sure many of you will find this funny.

Ok, after I saw that the hand vacuum pump was $30 at Autozone, I thought I'd be cheap and go for the milkshake method.

I connected my 4' of hose, had my son start the Expy and then was a bit surprised to feel suction on the end of the hose. I thought that's not what I expected, but the FTE guys haven't steered me wrong before, so I'll go for it. I put my lips on the end of the hose and it felt like the engine was attempting to treat my lungs like a thick milkshake. I'll pulled my mouth away and thought, I must be doing it wrong. So I gave a quick go again. Same result. Ok, I thought, I better go doulbe check and see where they said to attach my milkshake "straw". I had to laugh when I read that the hose went to the EGR valve. Here's where I had my 3/8" hose attached (passenger side of the elbow):

PIC - > IMAGE DUMP



I opened the 1/8" hose I had purchased to replace the broken lines behind the battery, reattempted my milkshake test, and was pleasantly surprised that the car wasn't trying to give my lips a hicky. Even better, my car started to stall, so I knew I wasn't going to have to disassemble my TB and dig out sooty ports.

Thanks for the help. Replaced my DPFE, fixed the small vac lines behind the battery and the CEL is off - hopefully for good. Well, at least until I have a hankering for another milkshake.

 

I had a similar prb with my 2000 5.4 ESPY. It ran rough and I changed the EGR and was about to change other parts when I found the hoses had dry rot cracks all the way through. I thought I could just use fuel lines but they would not stand the heat. The hoses are ceramic and sold by the dealer and some stores. Be sure this is not the problem either. fitzy67

 

If you aren't sure it's a DPFE don't go spend $130 at the stealership. Go to the local picknpull and get one for $10. Not only do ford pickups have them but the Focus uses the same one. I got 3 from the local yard for peanuts and now have spares a plenty. I'm sure they will take care of me as long as I have this expy.