What does Code P0401 mean

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Jun 13, 2006 | 10:55 AM

Clipper

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What does Code P0401 mean

I have done the search and know that blocked EGR valve ports and/or the DPFE are the probable causes of this code.
What is the effect on the Truck (2000 F150 5.4L 80,000 miles). ie Bad milage, run rough, bad shifting, etc.?
The Check engine light came on and I noticed no difference and was lucky in that I was able to get the code and now after about 20-25 miles the Check engine light is off.
Does this mean I no longer have the problem?
How quickly should one react to this code? i.e. fix it or have it fixed.

Be kind to the stupid questions.

Thanks

Duan

Jun 13, 2006 | 11:13 AM

fordpaul

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Clipper, I would encourage fixing/getting it fixed. If the dpfe is reading low, the engine management system will attempt to open the egr valve more with a higher duty cycle to the egr vacuum regulator, which will produce a surge on cruise due to the egr opening more than is necessary, provided that the passages aren't restricted. If the dpfe is reading high, the system will try to reduce the amount of egr flow to reduce the dpfe value, & can cause a ping, usually with no noticable performance concerns. I've seen p0401 codes which indicate insufficient egr flow usually caused by bad dpfe sensors, as well as vacuum supply concerns or restricted passages. May cause mpg concerns, due to everything being designed to work together with everything else in the engine management system.

Jun 13, 2006 | 06:49 PM

Clipper

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Thanks to fordpaul.

However does the check engine light going out and not returning for the last 20-25 miles (about the same it was on) mean the problem has cleared??

Jun 13, 2006 | 08:57 PM

projectSHO89

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From: St Louis

Quote:

Originally Posted by Clipper

Thanks to fordpaul.

However does the check engine light going out and not returning for the last 20-25 miles (about the same it was on) mean the problem has cleared??

Not necessarily, especially since you didn't do any repair work.

It'll be back..

Steve

Jun 14, 2006 | 08:34 AM

fordpaul

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Clipper, With that info I would tend to conclude that the dpfe sensor is going in & out of the proper range, which is not uncommon for dpfe sesnors. For sure, if the passages are restricted, they will stay restricted untill they are cleaned out. I immagine that there could be an intermittent vacuum supply problem, as well as a intermittently sticking egr valve or egr vac regulator, but most likely the dpfe is operating erratically.