Comments on: P0401 & P1408— Ford EGR codes, Fix clogged passages

By: Jack Bonanno

Jack Bonanno — Thu, 05 Aug 2010 14:11:30 +0000

I have a 97 ford duratec egr problem. Two new egr valves and I still get a code after a few hours of driving. What else in the system could cause the problem and where is it?

By: Rick

Rick — Fri, 16 Apr 2010 16:36:59 +0000

You can do a backpressure test on the cat to see if it’s plugged. But it’s more likely a carboned up intake manifold.

By: Sandi

Sandi — Thu, 15 Apr 2010 02:55:35 +0000

Hi I have a 97 ford f150 and I’m just sick of it now lol. I’ve had this for bout 5 yrs or so. It’s throwing a code P0401 Gas Recirulation, Insuficent flow detected, and exhaust. I have replaced everything with the stupid EGR 3 times now. I have no clue as to what is wrong with this. Do you think it could be the CATS that are clogged up? That’s the only thing I have not checked on or replaced. Please help if you can cause I’m at the end of my rope with this truck. Thanks
Sandi

By: franky2222

franky2222 — Wed, 16 Dec 2009 01:29:39 +0000

had i check at a great muffler shop they said everything looks good on the real time scanner exept that the cat in front next to the manifold seems to be 100 degrees colder than the other not sure what he meant .He said take it to ford and have them check it out to make sure. He dint charge anything for the hole checkup took 1hour.So i guess ill take it to ford next week to get to the bottom of this THANKS RICK for your quick reply once again HAPPY HOLIDAYS

By: Rick

Rick — Wed, 16 Dec 2009 01:12:11 +0000

No high end power and bad fuel economy can be caused by many things. If you don’t have a check engine light, the only way to diagnose this is to get a scanner on it with live data. You’d want to see what the “fuel trims” are, what the coolant temp reading is and what the MAF/MAP sensors are reading and how the O2 sensors are responding. Find a reputable shop with a good engine performance (ASE Master Tech with L-1 certification) tech and have them do the scan.

By: franky2222

franky2222 — Wed, 16 Dec 2009 01:04:54 +0000

well i replaced dpfe sensor last week code went away however i still have no high end power and bad fuel economy what could it be???

By: Rick

Rick — Tue, 15 Dec 2009 23:31:54 +0000

I’ve told you to clean the carbon out of the intake. Your instructor has told you to clean the carbon out of the intake. I’m getting the impression you’re looking for a magic cure here. There isn’t one. Unless you want to get an old speedometer cable and feed it into the passages and connect the other end to a drill. Then spin it down the tubes. That will clean out all the crud and it will all fall right into your engine. It’ll save you tons of time. However, within a week you’ll be shopping for a new engine. THAT’s why everyone says to remove the intake–so you don’t shove all that carbon in to the engine.

By: Chuck

Chuck — Tue, 15 Dec 2009 22:36:43 +0000

“Remove the throttle body and gasket. Behind the gasket you will find a half moon shaped passage with 3 openings into the intake manifold. Most likely you will discover that the passages are clogged with carbon buildup. Clean out the passages with a small pick and some throttle body cleaner. Then, install a new gasket and the throttle body. Your problem should be gone.”
Can this be applied to my situation? I went to the instructor to ask him what should I do after replacing both the DPFE and EGR valve, and he said that it’s time to clean up all that carbon. He told me on the ponies are two lines going to two ports in the intake from the EGR (I believe). I was quite confused, would you know what he’s talking about?

Instead of removing the intake to clean up all that carbon, is there another possibilty to remove the carbon from the intake manifold?

Thanks again.

By: Rick

Rick — Sat, 12 Dec 2009 16:35:43 +0000

Here’s the simple test. Apply vacuum to open the EGR valve at idle. The DPFE sensor voltage should go over 3 volts and the engine idle should change quite a bit. Engine should run rough and seem like it’s going to die. If that happens, then the EGR passages in the intake are good and allowing EGR flow. But if you don’t get those results, then the passages are plugged and you need to remove the intake and clean out the clogged passages.

By: Chuck

Chuck — Fri, 11 Dec 2009 23:17:45 +0000

I have the same P0401 DTC coming from my 2001 V6 Mustang 3.8L. I’ve researched through Mustang forums to find out that it could be the DPFE sensor. I am also a student at UTI – Rancho Cucamonga, and learned that Ford has problems with the DPFE being defected. So I replaced it, code went away for about 2 or 3 days. Then the CEL came back on, same DTC. I asked the instructor who has been working with Ford for over 15 years says that if the DPFE was replaced, and the CEL comes back on with the same DTC, then it’s probably a dirty EGR Valve being stuck closed. So I decided to replace the valve itself thinking “a new component=no worries”. CEL went off, but after one day, it went back on. Hooked up a scan tool once again to find the same DTC to appear.

I’ve been reading through these messages that you and these people have been discussing, and I’m beginning to think that it may be carbon build up. But where? Could it be in the tube that is mounted on the RH exhaust manifold to the EGR valve? Because, I’m thinking since NOx isn’t getting through sufficiently, then there isn’t enough to go to the intake manifold to result to a rich condition. Maybe?

Where else?

Thank you in advance,

Chuck