hello everyone, after reading some of the posts i know this is not a new topic.
i have 2000 b2500 with a 2.5 . the check eng light came on , went to autozone and had fault code p1401. which most of you know is the dpfe . disconnected the battery r/r the dpfe . drove the truck about 5 mi. turned it off and restarted it got trhe check eng light again. back to autozone got the same code . talked to a dealer and they told me to clean the intake at the egr valve . cleaned the intake and the egr valve and tube assy. checked my vacuum lines and all were good. disconnected neg battery cable to reset the codes pulled the fuses to the pcm. restarted the truck drove it about 5-10 mi. turned it off and restarted it and guess what the same fault. any help would be greatly appreciated.

 

the dpfe sensor is located on top of the intake and looks like this



Matt

 

Were you given the correct DPFE sensor???

There is an aluminum one, a plastic one & their are two vesions with dfferent operating voltages. A 0.5 volt & a 1.0 volt.

You can check it out here. http://www.tomco-inc.com/Tech_Tips/ttt36.pdf

I suppose you could have gotten a bad one, right out of the box. Just because it's new, doesn't automatically mean it's good.

Could also be a computer problem, I suppose, with a screwed up V-Ref!!!!!

Let us know what you find.

 

if it is a computer problem is there any way to check for it. i will be trying the correct
dpfe later today. i will let you know if it works . thanks for the input pawpaw.

 

BTW, welcome to FTE.

Just speculating here, but if you weren't given the correct DPFE, I might suspect thats the problem.

If that doesn't fix it, test for the reference voltage (V-Ref), that the computer supplies to the DPFE.

I suspect it's ok though, as your code isn't for no, or a low signal voltage, which might indicate a computer V-ref, or wiring problem, but the code is for too high a signal back to the computer.

It's looking at a table thats been programmed in & comparing what it's getting from the DPFE & other sensors, under the set of operating conditions the engine currently opeating under & is unhappy with what the DPFE is sending, compaired to what it's been told to expect.

So, if for instance you were given a defective DPFE, or a 1.0 volt at rest DPFE, but should have a 0.5 volt at rest DPFE, then the signal back to the computer will be higher than it's programmed in table says it should expect from the DPFE & that'll give it & you a headache!!!!! lol

Let us know how it goes.

 

well i'm currently trying my dpfe from another truck that currently does not have a check eng light and the the dpfe has the same p/n as mine. i will try to let you know how it goes.

 

OK, same P/N, DPFE, that should be ok.

Here is another link for additional more detailed DPFE info that you or others with DPFE problems, may find interesting or useful.
http://www.tomco-inc.com/Tech_Tips/ttt35.pdf

This file has some DPFE pressure operating tables vs output voltage, so you can back probe & do some operational DPFE testing, to see what's being fed back to the computer.

The DPFE's reference voltage from the computer to the DPFE is 5 volts. The signal voltage returned to the computer will be governed by the engines vacuum & differential pressure measured by the DPFE, depending on which "at rest" voltage kind it is & as outlined in the respective tables.

Just an additional info link, for what it's worth.

 

well so far my dpfe is in another truck and seems to be doing fine . if i don't get a check eng light . what else might cause the fault p1401.

 

try this.... (thanks to rockledge)

http://www.tomco-inc.com/Tech_Tips/ttt35.pdf

https://www.ford-trucks.com/lc/lc.ph...ps%2Fttt36.pdf

 

well my dpfe has been in another truck all day and the check eng light has not come on. that would indicate to me that my dpfe is good and there is something else giving me a p1401 code. any ideas . does anyone know if this would cause my truck to fail emmissions here in ga. does any one have any other suggestions as to what might be at fault. thanks

 

Well, is the new DPFE the correct one for the 2000 Ranger 4 banger?????

Did you have the hoses correctly hooked up, not reversed, to the new DPFE, on the 2000 vehicle?????

If all the above checks out, the Tomco site suggests, for a P1401 code, to look at the upstream hose & it's port, for obstructions.

 

my son is going to check out the dpfe that i put in my 2000 mazda that came out of a 2000 ranger . the dpfe from my mazda has been in the ranger all day that has been started several times through out the day. where as on the mazda i would drive the truck about 5mi turn it off and restart it and then the check eng light would come back on . oh btw i would disconnect the battery each time to hopefully erase the dtc. as soon as my son gets back i will let you know if the light comes back. thanks

 

um the codes dont just go away, it takes time

Matt

 

Heya, I'm, uhm...blackwidow's son...yeah... :P

Anyways, after about 2 days of sparkchasing, vacuum tests, etc etc...The problem has finally been fixed. Took the truck back up to Autozone, requested they pull the codes again, and figured we'd buy a new gas cap since we were there and because it was at the top of the list...

Voila! Problem fixed. Apparently the stock cap had become loose and didn't allow a vacuum to occur, and allowed fumes to escape.

So, thanks for your time and help guys. ^_^

 

Wild!! A bad gas cap causing a DPFE fault. What are the chances. What's the connection????Fred