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Diagnostic code P0401 Insufficient EGR Flow
New User
Joined: Jun 2006
Posts: 6
Likes: 0
ERG flow incificient
Hey I fould a great tip on another site regarding this code. I do belive people are being mislead into buying parts that are not nessicery, the ports to the throtle body from the egr valve are stupidly small, and clog easily.
To see if they are cloged, without taking the thing apart, hool a vacume pump up to the egr valve, and pull vacume, (not to much it was 5 to 10 on the scale on my pump) with the engine running in park at idle. When you apply vacume, the engine should supter and almost die, or die compleatly. If it keeps running fine, you tubes betwean the egr valve and throtle body are cloged for sure.
also a good tool for cleaning these, i took the end of an old pipe snake (a small one), and cut it to about 8", flared out the end, and put it in my drill, wa la power mini pipe snake, also heard old spedomiter cables can work the same way.
I spent hundereds of dollars and six months figuring out what this code ment on my truck. Hope this helps someone, i know if the shops i talked to knew this diagnosis methode my truck would have been fix MUCH quicker.
To see if they are cloged, without taking the thing apart, hool a vacume pump up to the egr valve, and pull vacume, (not to much it was 5 to 10 on the scale on my pump) with the engine running in park at idle. When you apply vacume, the engine should supter and almost die, or die compleatly. If it keeps running fine, you tubes betwean the egr valve and throtle body are cloged for sure.
also a good tool for cleaning these, i took the end of an old pipe snake (a small one), and cut it to about 8", flared out the end, and put it in my drill, wa la power mini pipe snake, also heard old spedomiter cables can work the same way.
I spent hundereds of dollars and six months figuring out what this code ment on my truck. Hope this helps someone, i know if the shops i talked to knew this diagnosis methode my truck would have been fix MUCH quicker.
Junior User
Joined: Jul 2006
Posts: 57
Likes: 0
From: Northern Illinois
I have a '96 F-150 w/ 5.0. Recently after changing the o2 sensor on the passenger side ( that was the biggest pain in the ***) my check engine light came on and it threw the P0401 code. What should I do? Is my EGR setup the same as the 4.6? Should I clean the ports?
Junior User
Joined: Jul 2004
Posts: 90
Likes: 0
From: Greer SC
I got the egr flow code... bought the egr from Autozone...
will take it off tomorrow....and clean the ports and report back.
great info on this board.... even if it's carboned ports..i figure a 98 trouble free expy with 153k miles deserves a new egr.
will take it off tomorrow....and clean the ports and report back.
great info on this board.... even if it's carboned ports..i figure a 98 trouble free expy with 153k miles deserves a new egr.
Freshman User
Joined: Jul 2006
Posts: 25
Likes: 0
Hello (new here) seems like most have the 4.6 with this problem, is everything pretty much the same on the 5.4?
E-250 van with 246,000 miles and 0401 code. My guess by reading is cleaning by the throttle body first, then go from there, but I am not sure if this is the same as the 4.6.
Wish I could see a picture of where the EGR is connected, etc to know for sure what the area to be cleaned out is.
Thank you - I have gain a lot just from this thread alone (read some others here too)
E-250 van with 246,000 miles and 0401 code. My guess by reading is cleaning by the throttle body first, then go from there, but I am not sure if this is the same as the 4.6.
Wish I could see a picture of where the EGR is connected, etc to know for sure what the area to be cleaned out is.
Thank you - I have gain a lot just from this thread alone (read some others here too)
Junior User
Joined: Jul 2004
Posts: 90
Likes: 0
From: Greer SC
well i did this job on Tuesday....
actually my check engine light had gone off.... in addition to putting on a new EGR (the old one was somewhat carbon-ed up) i sprayed brake cleaner through the port and took off the throttle body intake (4 screws) .
Inside the throttle body there was a port ( a hole inside the throttle body-- lower right on the throttle body) that was gunked up with hard carbon... a really need a dental pick or a pipe cleaner to clean it out perfectly, but it is in pretty good shape now.
i think spraying brake cleaner from the egr port help clean out the carbon-ed port. Sorry i don't have pictures. It becomes pretty obvious once you remove the egr and throttle body.
i bought a new gasket from ford for the egr....but i didn't need it..... it was 3 bucks and was metal.
the throttle body intake didn't need a new gasket either.
I would say it would have been possible to clean the old EGR... it had carbon build up that was similar to the ICV buildup I experienced a couple of years ago. I bought a new ICV as well.... however, I did cleanup and save the old ICV... I ditched the old ECR.
1998 expy 154k miles.
actually my check engine light had gone off.... in addition to putting on a new EGR (the old one was somewhat carbon-ed up) i sprayed brake cleaner through the port and took off the throttle body intake (4 screws) .
Inside the throttle body there was a port ( a hole inside the throttle body-- lower right on the throttle body) that was gunked up with hard carbon... a really need a dental pick or a pipe cleaner to clean it out perfectly, but it is in pretty good shape now.
i think spraying brake cleaner from the egr port help clean out the carbon-ed port. Sorry i don't have pictures. It becomes pretty obvious once you remove the egr and throttle body.
i bought a new gasket from ford for the egr....but i didn't need it..... it was 3 bucks and was metal.
the throttle body intake didn't need a new gasket either.
I would say it would have been possible to clean the old EGR... it had carbon build up that was similar to the ICV buildup I experienced a couple of years ago. I bought a new ICV as well.... however, I did cleanup and save the old ICV... I ditched the old ECR.
1998 expy 154k miles.
Posting Guru
Joined: Dec 2001
Posts: 2,017
Likes: 2
From: Southeast FLA
Question for all you guys who had clogged EGR ports, then cleaned 'em: Did the truck run differently (poorly or, even, better) with the ports clogged? I code I can deal with, but on some old engines a poorly-running engine's 'fix' was actually to restrict the EGR flow.
Thanks
Thanks
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Junior User
Joined: Jul 2004
Posts: 90
Likes: 0
From: Greer SC
i had notice on my last long trip.... i was having trouble averaging 19mpg in the expedtition...
i uusally get 20-20.5 on a 13-1500 mile trip.
i am making another long trip in a few weeks..it will be interesting to see if the new EGR improves or hinders MPG
i uusally get 20-20.5 on a 13-1500 mile trip.
i am making another long trip in a few weeks..it will be interesting to see if the new EGR improves or hinders MPG
Guest
Joined: Nov 2004
Posts: 7,988
Likes: 55
From: north west new jersey
Carefull guys pull the spark plugs out and crank the motor over for a while. Makes sure you don't hydro lock the motor and bend or brake a con rod .
It does not take much fuild to hydrolock up the motor and cause very heavy damage. And yes they will run rough and throw a possible missfire code till they clear up.
my own way is a set of picks and a old vacuum cleaner adapted up to smaller hoses to suck out the broken loose carbon.. another way is rifle cleaning brushes on a drill. to help better clean them out .
It does not take much fuild to hydrolock up the motor and cause very heavy damage. And yes they will run rough and throw a possible missfire code till they clear up.
my own way is a set of picks and a old vacuum cleaner adapted up to smaller hoses to suck out the broken loose carbon.. another way is rifle cleaning brushes on a drill. to help better clean them out .
Junior User
Joined: Feb 2005
Posts: 75
Likes: 0
DPFE definition
Originally Posted by woogs
well I went a researched it, it is the Differential Pressure Feedback System, The pressure sensor monitors upstream and downstream exhause backpressure. This backpressure coefficient is relayed to the PCM and the correct amount of EGR (duty cycle) is applied to the EGR Vacuum regulator control (EVR). By calculating the differences between the twp pressures, the PCM determines exactly the EGR flow rate at all driving conditions.
Freshman User
Joined: Jul 2006
Posts: 25
Likes: 0
OK, I took off the egr and I have a port about 3/4" (on a E250 van so I can see much else.) THe port seemed quite clear and had minimal carbon on the edges - even stuck my finger in there. I ran the van with just the egr removed from the port and it would die if I removed it completely and it seemed to have a ton of suction, so I am guessing it is clear.
Any other suggestions??
with almost 250k maybe the DPFE is dead? and if so can I check that with an ohm meter or voltage meter when running them motor? (seems like I read something back a few pages.)
Any other suggestions??
with almost 250k maybe the DPFE is dead? and if so can I check that with an ohm meter or voltage meter when running them motor? (seems like I read something back a few pages.)