Diagnostic code P0401 Insufficient EGR Flow
New User
Joined: Dec 2004
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Hi, I am new to this site. My problem is the transmission shifts every time you let off the gas pedal and put your foot back on the gas. It doesn't matter the speed or gear i am in. My check engine light is on also. My mechanic said to replace the egr valve, but it is clean. I have a 1997 ford f150 4x4 4.6 115,000miles. What do I need to do to fix this problem?
New User
Joined: Oct 2004
Posts: 24
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From: Springfield, OH
I had a similar problem, It was the throttle position sensor, it is like 25 dollars at autozone. The throttle position sensor tells the computer where the throttle is so it knows when to shift the transmission. It is very possible that you have a EGR underflow error as well, I fought with this repeatedly and finally resorted to tearing off the intake and cleaning it which resolved the egr underflow error. But for the shifting problem I would try the TPS first, it is real real easy it is right on the side of the throttle body on the top of the engine and you just have to unplug the connector and remove two phillps screws to get to it.
Hotshot
Joined: Aug 2002
Posts: 12,679
Likes: 15
From: BC, Canada
Hi Larry and welcome to the site 
When the check engine light is on or has been on there will be a trouble code stored in the truck's PCM (powertrain control module or computer). The first step is to get it scanned and see what the code is. That should get you pointed in the right direction.
I think that tmulkey is on the right track.
When the check engine light is on or has been on there will be a trouble code stored in the truck's PCM (powertrain control module or computer). The first step is to get it scanned and see what the code is. That should get you pointed in the right direction.
I think that tmulkey is on the right track.
New User
Joined: Mar 2005
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Originally Posted by hugepettyfan
Where is the most inexpensive place to purshase a DPFE sensor? My local dealer wants +/- $100
I am gonna try cleaning the ports next.
Senior User
Joined: Jan 2004
Posts: 227
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From: Tulsa, Oklahoma
Lately I've been having dreams of sitting in a different brand truck
and watching my P.O.S. '97 roll down a hill, in flames, heading towards
a deep lake. I wake up and smile. Oh well, only 2 years left to pay
it off. Maybe I'll have figured out why it won't start by then.
and watching my P.O.S. '97 roll down a hill, in flames, heading towards
a deep lake. I wake up and smile. Oh well, only 2 years left to pay
it off. Maybe I'll have figured out why it won't start by then.
Junior User
Joined: Mar 2005
Posts: 59
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well looks like i get to do the same thing everybody else has to do
p0401 it is.
so to clean the EGR i understand i think, but do i really need new gaskets or can i get by with the ones i have if i don't break them/clean them/treat them nicely?
i'm a penny pincher
p0401 it is.
so to clean the EGR i understand i think, but do i really need new gaskets or can i get by with the ones i have if i don't break them/clean them/treat them nicely?
i'm a penny pincher
Senior User
Joined: Jan 2004
Posts: 227
Likes: 0
From: Tulsa, Oklahoma
Clean the EGR ports, that is the important part. On the gasket,
if you can keep it from breaking, use it again. That can be very hard
to do, very delicate.
if you can keep it from breaking, use it again. That can be very hard
to do, very delicate.
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New User
Joined: Jan 2005
Posts: 3
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Insufficient Flow, thanks
Thanks to everyone for the info. about cleaning out the egr ports. I was told by and "expert" at Autozone that my problem was the sensor, $51. When that did'nt work it "had" to be the egr valve, $50. That did'nt work either. I was getting ready to purchase a new egr solenoid when I decided to hop online first and see if I could get lucky.
Hopefully this trick will finally get rid of the 0401 trouble code.
By the way, the truck is a 98 f150 with 192,000 on what has been a trouble free 4.6L.
Hopefully this trick will finally get rid of the 0401 trouble code.
By the way, the truck is a 98 f150 with 192,000 on what has been a trouble free 4.6L.
Last edited by ngerber40; Jun 17, 2005 at 01:07 PM.
Elder User
Joined: Sep 2004
Posts: 774
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From: Plano, Tx.
thanks to whoever brought this back to the top. I just got the P0401 code. I have the 4.2 V6 with just under 61k miles. so from what I read I should replace the DPFE. first of all I don't even know what a DPFE is, and will this one fit my truck? Ebay auction number 7980513777, the part number is F77Z-9J460-AB. is there a way I can check the old one to see if it's bad before buying a new one? I don't guess I have enough miles on it to think I oughta clean the ports, but I guess it couldn't hurt.
-thanks
-woogs
-thanks
-woogs
Hotshot
Joined: Aug 2002
Posts: 12,679
Likes: 15
From: BC, Canada
Hi ngerber40 and welcome to the forum
Please let us know if you get it cured.
woogs I would try applying vacuum to the EGR valve with the engine idling and see what happens. If the ports and valve are ok the engine will stall or almost stall and then it's safe to assume that the DPFE is the problem.
A F77Z number is from a 1997 truck. Ford has changed up the DPFE since then so I'd go to your dealer and buy the latest one.
Please let us know if you get it cured.
woogs I would try applying vacuum to the EGR valve with the engine idling and see what happens. If the ports and valve are ok the engine will stall or almost stall and then it's safe to assume that the DPFE is the problem.
A F77Z number is from a 1997 truck. Ford has changed up the DPFE since then so I'd go to your dealer and buy the latest one.
Elder User
Joined: Sep 2004
Posts: 774
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From: Plano, Tx.
Originally Posted by truckfanactic
What is a DPFE?
New User
Joined: Apr 2002
Posts: 16
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Has anyone else experienced this code due to the recent bad gas from union 76 in the western Washington state area? The local dealership charged Conoco-Philips 100 bucks to pour a can of injector cleaner in my s.o.'s truck, and then they said "they didnt get paid to turn the cel off". 02 ranger 47k miles, you think they wouldnt break while you were still making payments huh?
keep this thread up toward the top, its a big hit from google on DPFE, which has a LOT of problems that refineries didnt cause...
keep this thread up toward the top, its a big hit from google on DPFE, which has a LOT of problems that refineries didnt cause...
Last edited by ramdodger; Jun 20, 2005 at 01:50 AM. Reason: added info