With a DPFE I would only buy a genuine Ford one as they have changed them up lately and they appear to be better than the old ones.
Yes a bad DPFE is common. So much so that Ford has come out with "streamlined diagnostics" for them.
If a vehicle comes in with a Check Engine light on we are to scan it and if it's a P0401 we are to replace the DPFE and ship it out the door without checking anything else
It's totally not the way they teach us how to fix things but they are trying to save a buck by coming out with stupid ideas like that. Really though it does cure the problem most of the time as long as it's not a high mileage vehicle.

 

Hey Racerguy,don't you just love it,they teach us fix it right the first time,then they give us .3 to diag and change the parts.I always use the NGS,wds will waste .3 just setting up,and i always pid it out just to be sure because i hate comebacks.

 

I'm waiting for one that the DPFE doesnt fix it so it comes back and gets scanned again......P0401.....replace the DPFE again. Next day, same thing etc etc etc.
Things like that do wonders for Ford's customer satisfaction.
"I'm sorry sir but Ford says that all I'm allowed to do is replace the DPFE"
Sorta like the Focus fuel pumps. Replace them and see if it fixes it. If not then do some diag on it
Do I sound a wee bit bitter?
lol

 

Yup, buy them books teach them to properly diagnose and then, no don't do that just repace parts. When that doesn't work then diagnose! Oh yea, have fun getting paid for diagnosing the p0401! Thanks ford.

 

My 97 F150 would have been one of those callbacks. At 95,000 I had the P0401 code. I changed the DPFE sensor, only to get the code again, followed by a P0302 (#2 misfire). I just dismantled the throttle body to find the EGR ports completely clogged by carbon. I'm still getting a CEL, though and have to go borrow Schucks OBDII scanner to see if it's still throwing 2 codes. I suspect that took care of the P0401 code, and what's left is the P0302. Keep your fingers crossed! I didn't change the EGR valve (cleaned it), so that's next if I still have the P0401.

 

After I changed the alternator, cleaned the maf and egr ports, replaced the egr valve,
it still read a lean bank code, althought it was really an IAC problem. When the
IAC part came in a couple days later, I switched it out and reset the computer again,
code went away, runs great now. Any up and down idling Elk? Also, the new egr valve should fix that code for you. EGR valve cleaning doesn't really work well, althought port cleaning is a must around 90-100k+

 

Okay, the P0401 code is gone, although I still plan on swapping the EGR valve when I find one on ebay. When the OBDII scanner ran it through it's EGR scan, it actually changed idle, which it didn't before the cleaning. So, it seems the thorough cleaning did the trick. I haven't had any up and down idling problems... but am keeping the problem in mind, considering you can almost chart the problems that these 4.6l are going to have.

Still have the P0302 #2 misfire, though. I've swapped coils (dumb, dumb, dumb... why didn't I ohm them?), and plugs. My next move is the ignition wire. The misfire makes it run like crap. Funny thing though, when I accelerate (stomp the pedal), no misfire.

 

I've read a few posts saying that on a high-mileage 4.6L the DPFE is seldom the problem, but I checked my EGR and all a couple weeks back and it was clean...really clean, to my amazement ('97 with 129000 miles)

Then I started looking at the DPFE...did what my Hayne's manual said and checked for reference voltage on the DPFE...nada...

If that's the case (this is just as a precaution...measure twice, cut once, etc), then the DPFE IS the problem, right?

Just making sure

Thanks in advance.

 

If you're sure you dont have VREF (reference voltage) at the DPFE then you have a wiring or PCM problem. Usually the VREF is ok though and you need to replace DPFE.
VREF should be 5 volts on the grey/red wire.

 

Make sure you are actually checking the EGR "Ports" not just the EGR valve. My EGR valve was fine, my ports were 100% clogged and took a long time with a coat hanger, my leatherman and an entire can of throttle body cleaner to clean out the ports. I'm not saying the DPFE cannot be the problem, I'm saying that on a high mileage 4.6l look to the EGR ports first. You need to remove the throttle body neck that sits between the throttle body and the intake manifold. You'll need two gaskets to put it back together. If you remove your valve you'll need a third gasket. My DPFE was still kind of cruddy, but it was not what was throwing the code.

Even if you replace the DPFE, it's a good time to clean those ports.

BTW, the P0302 (#2 misfire code) was nothing but a bad wire. Now THOSE were harder to replace than cleaning the EGR ports!

 

I have a '97 F150 4x4 with 168,000 miles. It's giving me code P0401.
Is cleaning the ports as tough as changing plugs? When I take off the EGR valve,
will there be a gasket to replace?

Thanks for any advice

 

A new egr valve should come with a gasket. You'll probably need a new one for the throttle body housing. It's not as hard to do as spark plugs,
just different. Believe me, it is well worth any trouble encountered.
Is yours a 4.6? Enjoy the new performance.

 

Yes, it's a 4.6. I've had really no problems with it, gas milage has gone down some
I'm hoping it's related to this problem

 

I imagine you'll notice quite a positive difference.

 

Thanks for your advice.I have a 2001 Expedition with the same 4.6 in it. I guess
this will be a good learning curve.There's a world of difference in later model trucks compared to a 1970 F100.
Thanks again.