Please help. I've had a 0401 code on my truck for the last two years. I've replaced the EGR valve and the dpfe sensor a couple of times, with fomoco parts. Ive also cleaned out the egr tube that comes off the exhaust manifold. In this time I also discovered a couple of vaccum leaks and replaced those. I changed the pcv valve, tried running 93 octane gas, and had a mechanic friend run a special smoke through the vaccum lines to find more leaks. Also put a brand new gas cap. I have an obd computer and cleared the code repeatedly but the light always returns. Some one please help or have an idea???

 

Thread Moved to the '97-'03 F-150 forum
from... '09-'10 F150 forum.

Welcome to Ford-Truck Enthusiasts!!
Based on looking at your profile I moved your thread here. In the future you may want to include your year/model/make and engine size.

I'm pretty sure the guys in this forum could help you out with the code that your getting... Good Luck!

 

The line that runs from the DPFE sensor to the throttle body is likely blocked.I suggest removing the throttle body and cleaning all ports forward,and AFT of the throttle plate.The Original DPFE modules were made of a metallic substance,that was prone to corrosion in the exhaust stream.This is a combination of carbon,and water.The newer sensors are plastic,and seem to resist this corrosion.

 

Sorry I didn't specify the year, make, and model. It's a 98 ford 150, 4.6l. It's fuel injected so there's no throttle body. The dpfe has two hoses that go to a metal tube that comes off the exaust manifold. And yes I cleaned it out. Any other ideas.

 

My 97 was a 4.2 and there is in fact a throttle body. there isnt alot of difference between a 4.2,and 4.6,except that the 4.2 is a v-6,and the 4.6 is a v-8.Along with a little more HP,and some spunk.

 

What's the purpose of the throttle body when there is two fuel rails (one on each side of motor) and 8 individual fuel injectors? And I just checked there are no lines coming off the dpfe going to the the area where the throttle body should be. The two lines go the the egr pipe which in turn ties into the exaust manifold(drivers side).

 

There are two types of fuel injection systems,one(earlier version) had one Fuel injector )(sometimes two) mounted in the throttle body...Thusly "Throttle Body Fuel Injection" this was typically used on 4 banger cars and small trucks. The later version was cylinder fuel injection. This used an injector for each cylinder such as our trucks,and cars.Our throttle bodys are merely an opening with a circular seal that opens as you push the gas pedal. It controls the amount of air allowed into the engine,along with metering this air to control ignition timing,duration,and computer control to fire the injectors.The Throttle bodys we have incorporated the TPS..Throttle position sensor,as well as orfices forward and aft of this seal previously mentioned.MY EGR port on the old 97 was located aft(behind) this seal(Plate) and it was carboned up so bad there was no engine suction being sent through the DPFE to the egr,and that is what gave me my code.This may or may not be your issue,but you DO have a Throttle Body.

 

just to be safe remove throttle houseing not the front but the bottom half i think there 10 mm bolts if clean then try switching the dfp lines around could have gotten mix up
i did it my self did have same code replaced the same things you did butt it was just the lines

 

There are two ports inside the throttle body itself that will cause a P0401. Have you cleaned those?

 

Sounds to me like the like the egr ports are clogged. Also, the 4.6 and the 4.2 are VERY different engines. Other than some electronics that are common to all fords, they have nothing in common.

 

I did take off the throttle body. I did find that the two ports were 80-90% clogged. I reassemembled everything. I thought I had fixed eveything, and got a good 70 miles on the truck before I got the check engine light again. I have a obd2 code reader, and of
coure it's that 401 code again. I have a 98 ford truck, 4.6l, fixed all vaccum leaks, replaced egr valve and dpfe valve twice with fomoco parts. Cleaned out all ports on the throttle body. Any other ideas guys. This has been a two year problem and I'm about ready to buy a chevy just out of spite. I've got a 69 rag top, 71 Mach 1, and gran Torino dont make me go to the dark side.

 

Did you hook the hoses up backwards on the dpfe? Thats a common problem. Also make sure that the carbon is completely cleaned out and the connectors are all plugged in.

 

Yes sir. I cleaned out all the ports to a high shine. The looked brand new when I got done. It took me a good couple of hours. And on the dpfe one hose seems to be slightly bigger. As is on the egr tube that to the exaust manifold. I got the top tube onthe egr tube going to the connection closest to the fire wall and the other below it going to the connection towards the front of the motor. Just out of curiosty... What color is the vaccum tube going to the egr valve itself? I'm willing to try anything at this point. I got and inspection coming up this month, All ideas are welcome. They won't pass it with a check engine light on.

 

Let me know how yours are hooked up. Think it possible so carbon got
loose and fouled up my new dpfe or egr? Think I may need a new computer?

 

switch your hoses on the dpfe, reset your computer and let me know what happens. im pretty sure the top hose on the egr tube goes to the port closest to the front of the engine.