This job is more involved, but not more difficult than changing the plugs or wires. In a nutshell you'll have to do the following... (get a repair manual for complete info).

1) remove the throttle body plastic cover.
2) Remove the air cleaner assembly.
3) Remove some TB linkage and then remove the throttle body.
4) Disconnect your EGR valve from the back exhaust pipe. It's a bit of a pain. Remove the throttle body neck.
5) Using TB cleaner, a hanger and a small pick of some sort (I used my leatherman wave tiny screwdriver bent at a 45 degree angle) chisel through the carbon build up on your EGR ports on the inside of that neck. The holes are actually about the diameter of a little finger. This took a while.
6) I took off my EGR valve as well and cleaned what I could of that port, etc.
7) Make sure you clean off the old gaskets and don't drop a bunch of gunk in your intake manifold (I put a clean shop rag in there while I was working. Don't forget it!
8) Assembly will take two new gaskets (throttle body, and between the neck and the intake manifold... about $12) Also, you'll need an EGR valve gasket... about $3. Many say this is the time to replace your EGR valve. It makes sense, so you won't have to do it again.
9) Good time to spray some electric cleaner inside your MAF sensor port (where the little filament is) before reassembling the air assembly.

I may have missed something, so someone please reply if I did. However, I just followed the steps for dissassembling the throttle body in my Chilton manual. I also had the ford dealership print a part explosion of the throttle body and intake manifold when I was buying the gaskets.

 

By EGR ports do you mean the two ports that the holes on the EGR valve connect to/line up with?

Maybe I'm just naive, but IF they are connected to the EGR valve itself, why would the ones on the EGR valve be spotless, and the ones on the TB be filthy? Wouldn't there also be a buildup of carbon in the EGR valve?

Thanks in advance for the clarification.

 

It's the backside of those very same ports. They're inside of the throttle body neck. Remember that the flow of exhaust goes through the EGR valve, through this convoluted maze of ports and into the intake manifold. So, the blockage is at the end of the ports. Once you see it you'll understand why. I don't guarantee that's the problem. If you feel confident they aren't, you can wait and see what happens. However, what I've learned from this forum, and then proved with my own experience, is that these blocked ports are extremely common, and probably guaranteed.

 

I have had this PO401 code for longer than I want to admit, but my truck started running rough, missing and the check engine light flashing (misfire?) I have a 98 f150 with the 4.6L, and 120000 miles. So a friend of mine and I began Sunday after church to take the throtle body apart so it could be cleaned. Thanks to Elktrekker, Racerguy and others on this forum we ran into no surprises. I had purchased at a local Ford dealer an EGR gasket and throtle body gasket and while I was there the counter guy talked me into Ford's Carb Cleaner. The cleaner works!!! The one gasket I did not get was the one for the intake manifold. O'Reily's had it!

Got the parts needed, cleaned the egr ports (talk about being stopped up!) and while everything was off the engine, changed the spark plugs! The tip on using twine to get stubborn boots off helped out. Oh yeah, one tip I have, when taking the throttle body off, place a towel around the area you are working so not to lose tools, bolts and things down the manifold casting into the 4.6 abyss. Also find a long 10mm socket for the egr bolt next to the firewall. I should be able to get that extension out someday, I hope.

After putting things back together, truck is running great and no code. Thanks to the forum and an extra pair of hands everything went great.

 

Good to hear that you got it done

 

I am new to the site. I must say, like Kd5tcl, I have had the P0401 code for a very long time. I will thoroughly clean the EGR ports and let you guys know the results. By the way I have a 99 Explorer with 125k miles.

 

What size engine in your Explorer?

 

I've got a '94 T-Bird with the 4.6 & 110,000 miles that's giving me the same problem. From what I'm reading here, it sounds like the ports need cleaning. Just how hard is this? When my check engine light came on (literally 1/2 mile after leaving the repair shop after getting a new water pump put in) the mechanic checked the code and said it was an EGR problem, but that until he took everything apart he couldn't tell if it was the valve, the ports, or what. Kept saying what a big job it would be, lots of stuff to take off, $3 -$400, blah, blah, blah. He cleared the code, and the MIL didn't come back on for 9 months. Now it comes on about once every two months, lasts a day, then goes out again. I'd like to clear it up once and for all, but don't want to get in over my head. btw, the light initially came on after the mechanic left it idling for 30 minutes to make sure the water pump wasn't leaking. Think that had anything to do with it?

 

There are detailed instructions on this forum for cleaning the ports, just scroll up. It's a detailed job, but not very difficult. It should take a couple of hours to a half day depending on your experience and speed. After doing it, there's no way I'd pay a mechanic the kind of money they're asking to do it. Most likely it's not the valve or the sensor. I'd clean the ports first... especially with your kind of miles.

 

Hi Vegas

Check the extended warranties on your Ford I seem to recall something about a extended warranty on a tube mounted egr bringing it to 5 years

John

 

First, I would like to say hello to everyone as this is my first post here.

Secondly, I too have come up with the dreaded P0401 code. My plan of action is to first clean the EGR ports to see if that indeed clears the code before I move on to replace the dpfe sensor.

My question is this: what specific solvent should I use to clean the EGR ports? I have heard the inside of this throttle body has a special coating on it to increase flow?

Vehicle:2002 F-150 FX4 4.6L 41,000 miles

 

Hi FS-150 and welcome

I use Carb-Medic spray carb cleaner to clean things like that, but dont get any in the actual throttle body because it will eat the coating.
The coating is there to resist deposits in the throttle body. You can buy throttle body cleaner for cleaning it and I think it would work ok in the EGR ports as well.
Before I went to the work of cleaning the ports I would do a bit of testing first. With the engine at idle, apply vacuum to the EGR valve and if the ports are clean and the EGR valve is ok, the idle speed should drop or even stall. If it doesn't then the ports are plugged up or the EGR valve itself isn't opening.
If the idle drops or the engine stalls then the most likely suspect is the DPFE sensor.

 

Thanks for the welcome Racerguy. And for the advice! I will give that a try tomorrow if I get a chance, and post the outcome.

 

I have been away from this site for many moons. Kinda got out of the truck hobby and into another. But I have returned out of neccessity. Before I stopped coming to the FTE website I spent alot of time in the 1979 forum as a hobby. Now my daily driver has delivered the same P0401 code being discussed in this thread. Purchased a code reader from e-bay (never needed one of these things dealing with the old 79s!) and on the day the reader arrives the "Service Engine Soon" light goes out. (haven't even got the reader out of the box yet. Anyway, plug the reader in and there it is "0401" but the service engine light is not on. I suspect it will be back, it is a 2001 F150, 4.6. with 45k miles. I will check the EGR with vaccum this weekend but with only 45k miles, what are the odds of having plugged up ports?

 

I had a F150 2002 4.2 125k Miles. I had misfire when stomping on the gas, I would let off the gas a little and it would pick up. It seemed worse when cold. I replace plugs and wires and it got better for a couple of weeks and got worse. Also I was fighting withe the check engine light. I was getting the 401 error. On the 401 error, I went to http://www.harborfreight.com/cpi/cta...emnumber=46030 and bought a generic odbII scanner for 40 dollars, which was cheaper that one trip to a shop to get it cleared. It works great you plug it in and it flashes the codes 4 times, after the 4th time it clears them, if you dont want to clear it then unplug it before the 4th time. It is called a Creader and I have seen them on ebay for about 50 dollars. I replaced the egr valve and it came back. I took the DPSE valve off and hosed it down with some b12 chemtool and sprayed the houses and tube out good to, since that no 401 error. As for the misfire, I removed the plugs(Bosh 99cent jobs) again and replaced them with autolite platnums an no more missfire. The guy at autozone says that the newer engines run to hot and the resistor in the cheap ones breaks down, I don't know if that is true, but the more expensive plugs work great.