Diagnostic code P0401 Insufficient EGR Flow
Hotshot
Joined: Aug 2002
Posts: 12,679
Likes: 15
From: BC, Canada
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.
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.
New User
Joined: Jul 2003
Posts: 17
Likes: 0
From: Blind River Ontario
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.
Hotshot
Joined: Aug 2002
Posts: 12,679
Likes: 15
From: BC, Canada
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
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
New User
Joined: Dec 2003
Posts: 16
Likes: 0
From: Idaho
DPFE or clogged EGR ports
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.
Senior User
Joined: Jan 2004
Posts: 227
Likes: 0
From: Tulsa, Oklahoma
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+
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+
New User
Joined: Dec 2003
Posts: 16
Likes: 0
From: Idaho
Good News!
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.
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.
Junior User
Joined: Mar 2003
Posts: 66
Likes: 0
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.
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.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
Hotshot
Joined: Aug 2002
Posts: 12,679
Likes: 15
From: BC, Canada
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.
VREF should be 5 volts on the grey/red wire.
New User
Joined: Dec 2003
Posts: 16
Likes: 0
From: Idaho
DPFE vs. EGR Ports
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!
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!
Freshman User
Joined: Jul 2004
Posts: 25
Likes: 0
Try'in Hard
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
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
Senior User
Joined: Jan 2004
Posts: 227
Likes: 0
From: Tulsa, Oklahoma
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.
just different. Believe me, it is well worth any trouble encountered.
Is yours a 4.6? Enjoy the new performance.
