Hi, I've a '97 F150 4.6L with 377K. It runs very nicely, looks good, seldom an issue (I do some of the work, smaller things but have
had good mechanics as well)...
I've noticed a bit of a 'bump' or 'surge' while at highway (45-55) speeds ... it is a definite bump and doesn't feel like a 'tranny
searching' for a gear.
I put a code reader on it (no CEL but I think the little light is out - gotta see how to replace that) and the CODE came out
P0401 and P0402 - I checked as many vacuum lines and connectors to the EGR and into the solenoid, cleared the code.
I checked two weeks later because I was still feeling that 'bump'... now only the P0402 is showing BUT suddenly a P1405 (Man. Control)

I have had EGR issues for some two years and believe once before we had this "bump" while driving.
The EGR Valve has been replaced and the EGR Solenoid... the "tube" has not but I Need to check as I did have
one to replace it with and (being old) I cannot recall if I did. My records aren't showing that.

I do not recall ever cleaning the EGR ports ???

Any comments or help (I've searched and did find a lot of input but not with the MIX of P0402 and P1405)
GREATLY appreciated. thank you.

 

Clean the EGR port

 

Yes, I do believe that will solve it... my issue is "degree of difficulty" which sounds like a woosie... but
I have an injury and leaning into the engine bay is no longer "a piece of cake"... may end up taking to faithful
but expensive mechanic. Thanks for the input... LET ME ASK YOU, is there a kit to your knowledge
to replace all the vacuum lines or is that a cut n paste? Thanks again.

 

A clogged EGR port will cause a P0401 (insufficient flow), not P0402 (excessive flow) or P1405 (upstream DPFE hose) codes. Gross blockage of the EGR flow can be checked by manually applying vacuum to the EGR valve at idle and see if the engine stumbles or even dies.

More likely than not, there is an issue with the DPFE sensor. Contradictory and spurious codes coming from a single sensor usually points to a sensor failure. Use ONLY a Motorcraft sensor.... aftermarket ones have been hit or miss over the years. Original DPFE sensors from this era failed at very high rates and Ford came out with a revised sensor way back, maybe 15 years or so ago. A SEARCH of old threads from 10-20 years ago will show the prevalence of these failures.

The surging may well be due to either un-commanded EGR flow or from the PCM compensating for factors that should counter EGR flow that isn't happening as anticipated.

 

Thanks Project...
I did have the '01 and '02 CEL and 1405...Insufficient and excessive, and the 1405 is a PCM/manufacturers control. I have seen that the
DPFE sensor is the cause in so many cases. My old Ford F150 (377K, '97, bought new and garaged its whole life) has been loyal
and I cannot ever sell her. Other than this the truck runs so splendidily. I put a very nice Eaton in the back and can drive in almost
any weather and many sticky terrains. Gotta fix this and will look into the DPFE. I always try to find Motorcraft... agreed!
Thanks very much

 

Update... DPFE... I have the 'original' DPFE device (aluminum - 25 years old)... I bought the 'new' Motorcraft DPFE to replace it AND (the subject of this issue) a new connector harness (Motorcraft doesn't make them or no one has that version) so this is an NTK harness..
I checked the 'wiring schematic' from Ford and note the correct color codes on the 'stock harness' but that doesn't help me configure the new 'WVE by NTK' harness. Should I just wire (have to snip and connect as the actual plug fits the new only) left to right and assume the "old original DPFE" has the same internal wirings as this latest version of the sensor? I will attach a couple of photos to present the issue visually. Thanks for any help.

Original DPFE

New Motorcraft DPFE4

Old harness connector won't fit new

 

Anyone got an idea? There is no schematic for the new DPFE to determine which is the correct 5v connection, etc..?

 

So this part (sorry it is Amazon but Rock Auto has it as well, see rest for issue) is EXACTLY like the 'old aluminum' part, same exact plug out, bolts to engine (4.6L '6' motor in '97 150 XLT Supercab) just like original part...
https://tinyurl.com/445nxkwa and 1A Auto indicates in vehicle fit (https://tinyurl.com/mweyvzfk) that it fits the '97 F150 Pickup ... A FEW PLACES indicate that this part "only" fits a 5.4 but in reading I see
countless persons installing it to replace a bad DPFE on their 4.6L so I am contemplating dumping all the "wiring issues" and using this with the original 'connector/harness' and seeing how it goes? ANY thoughts, anyone?

 

Done... waiting on the DPFE15 that 'looks' identical to the 'original' aluminum part I am replacing (1997 - 375K). The DPFE4 had completely different appearance and plug. So.... I learned that some part sites, even respectable ones with a long history of service and help to the "do it yourself" groups DO NOT KNOW what part fits what vehicle and will say absolutely that it won't fit while 70% of the other similar vendors will say emphatically that it does. Very confusing. Ford is not much better. So in this case I went with the 70% group indicating that the DPFE15 would fit my '97 F150 4.6L "6" motor... XLT. The whole throttle body was removed and cleaned and the intake under it also cleaned (the ports, used a scope to see 'em) were very clean (engine had major head work done 3 years ago, prophylactically, so it would seem that they got scrubbed. Put a new IAC on as well, ports in that were dirty. Checked all hoses, looked firm and no leaks but I suppose a smoke test might be in order if the new DPFE doesn't stop the P0401 'and' P0402 (at once) codes. Lots of interesting information on the sites as well. Cruise control linkage to the passenger side of the intake and TB is removed by lifting VERY firmly UP and it pops
off ('97 F-150, 4.6L '6' motor, XLT version, 3rd door) but NOT out to the side! That will break it but several people in different locations all had placed that direction in their 'how to' for the exact same truck. Strange. Guess all's well that ends well. Have new
part Thursday and will advise if it cures the double code. Thanks.

 

You just got the wrong plastic one
You need the one that has the hoses coming out the bottom of the DPFE like your old aluminum one
I have seen the plastic ones be an update for the 1998's OEM aluminum ones

 

Yes, it seems that way 'however' many outlets 'suggest' or list that part as the replacement one. I spoke with a friend
who used to work for Ford and he said some parts go thru so many iterations that 'no one' has any idea which one
is just right... we'll see, it arrrives tomorrow. Thanks very much!!

 

I still look for the aluminum ones myself
They are getting hard to find
I replace about a hundred a year and have to use the plastic ones often
I cringe
They don't all interchange
I do get a few at the junkyard when people do not have the hundred bucks for a new or reman one