I have a 1997 F150 4.6. I had the code years ago and got introduced to the cleaning of the ports in the throttle body. So here we are years later with 146,000+ on the engine and I get the P401 code again. First thing I do is clean the ports. Not really clogged but cleaned to shiny new anyway. Code comes back after reset with code reader. Next stop was DPFE switch replacement. Code came back.. Did EGR suck test engine about stalled so EGR valve good to go. Checked vac lines found two broken and cracked behind battery at firewall and fixed them. I thought I had the code fixed for good but nope code came back again. Changed EGR Actuator just because it was the last thing to do. Still the code came back. Cleaned Throttle body ports again thinking I missed something but still nice and clean. Took DPFE switch back to CarQuest and got another one. Code still came back....I have no idea what else is in the system that could cause this P401 code to continue to come back. Any idea or thoughts would be greatly appreciated.

Thanks and Sempre Fi to all my fellow Jarheads.

 

theres one problem. put a motorcraft dpfe on it. most aftermarket dpfe's dont last long. tomco is so far the only aftermarket to last a while for the aluminum dpfe's. did it have an aluminum dpfe or plastic? they were different as far as signal goes. you need to make sure you get the right one. also check the hoses that go to the dpfe.

 

Both of the new ones were after market DPFE plastic ones

 

what was the original? like i said they produced different signals.

 

ford aluminium Where can I get TomCo part? Ford wants like $128 for new DPFE

 

i dont know but user jbrew will. i'm sure he'll be in here.

 

NAPA sells a DELPHI DPFE ever heard of it?

 

I have been through the same circumstances you have with my 97 4.6. It's like that light is supposed to be on, or something isn't right. Mine is an early 97(build date April 96). The dpfe that was on it when I got it was aluminum. The first time I went to the dealership for one they tried to sell me a plastic one. Having read about the voltage differences between the metal and plastic ones, I've always had the metal one on it. I'm beginning to think maybe I should try the plastic one, but I just don't want to waste money on something I can't use.
I have read over, and over, in this forum that the aftermarket ones, do not hold up. But in my experience the Fomoco brand isn't so good itself. I've polished, cleaned, checked and done everything but buy the factory plastic one. But the cel is on as much as it is off. The code is always the 401.
The one time I got it to stay off for a whole year was when I replaced the EVR(as you stated you did). But the one that is on there now seems to be working properly.
I hope you can come up with some answers for me.

 

I have had a similar issue with my van Replaced everything still had the code took it into Ford and they reamed out the tube in the exhaust manifold and the code has been gone since. Ford sold me a plastic DPFE to replace the metal one (that I should have kept because it was probable good along with the EGR that i replaced..)

 

We may have a problem here - I'm finding stuff out there on the net that says that the aluminum DPFE is discontinued and you have to replace it with plastic now. The Rock Auto catalog does say that the Delphi is reboxed OEM.

Aftermarket DPFE's are NOTORIOUS for not lasting very long, or even work at all.

From what I see, the reason for plastic is the aluminum ones have a tendency to corrode when moisture gets in them.

 

Are you talking about the orifice tube in the EGR pipe?
Also should I go get a plastic one. Because my CEL is on again and I'm gathering parts for the 200,000 mile tune up. Of course I will only do one of the jobs at a time, so I don't create multiple problems.

 

Yea , I was just over at TOMCO trying to look up a 97. - No Dice.

http://tomco-inc.com/Emission_Sensors_9180.aspx

Then I tried to look the one up I purchased a year ago or so from them. - Denied!

What's up with that ? That sucks.

 

humm...my DPFE was plastic and i replaced it with a motorcraft part and it was around 54 bucks and my CEL went off

 

yours didnt have a metal one that year. you have a different one i think. yours is the one that just slides on the 2 hoses right? yours didnt bold onto anything did it?

 

yea mine had 2 different sized hoses and a electrical plug on it by the master cylinder