Hello All,
I have a '99 Ranger, 4L V-6 4X4, roughly 62K miles, recently the Check Engine Light came on. I checked the DTC and it showed a P0401 <!--StartFragment -->Exhaust Gas Recirculation Flow Insufficient Detected. The symptoms are- it knocks horribly under load, gas mileage is down, and it seems to have lost a little power.

The local Ford dealerships I've talked to are bent on hard-selling the routine dealer maintenance ($650 + parts + whatever else they think needs to be fixed at full dealer price-- they wanted $120 just to read the DTC!!). I am on a limited budget and would like to do this myself as inexpensively as possible, and I'm hoping somebody with experience with this can suggest whether these symptoms are related to the EGR needing replacement or if this indicates a problem with the DPFE. Replacing both would total about $140-150 in parts, and looks to be within my mechanical abilities, but I've read some postings in other forums where people have replaced one or more components without resolving the problem. I would like to try to get a better idea of where the fault lies before I start throwing new parts (and my money) under the hood.

I would really appreciate any advice you can offer me for dealing with this. Thanks in advance.

Edward

 

Check the technical articles to get more info. It might be something as easy as a little carb cleaner. Good luck and keep us posted. Don't spend a bunch of money yet!

 

Welcome to FTE!

A malfunctioning EGR system can contribute to engine knock (pinging), since the whole purpose of EGR is to reduce combustion chamber temperatures (and hence NOx). High combustion temperatures are one of the primary causes of pinging, although there are several others you also have to consider. In your case, you have to start by fixing your EGR-related problem, and then you can go from there.

The P0401 is a common EGR-related code, in fact there was a recent thread on the subject which has a lot of information that can help you.

https://www.ford-trucks.com/forums/s...d.php?t=228156

(P.S. If you feel you can replace something like a DPFE and EGR valve yourself, then you are more than capable of fixing this problem on your own, because IMO that's about the most a dealership would do for you to resolve that code, anyway.)

 

Hi again,

I hope this isn't premature, but I think I resolved it. Followed the instructions in Rockledge's reply and tested the DPFE and the EGR valve.

The DPFE was really tough to backprobe, but I was not about to splice any wires in my engine. It seemed like it was losing a little vacuum, and when I placed the probes in the wiring harness as best I could, it would jump up out of range, then slowly drop bit by bit down below the voltage it should read. The EGR valve held vacuum, and performed as it should when I disconnected the IAC and pulled a vacuum while the truck was idling. Based on this, I bought a new DPFE from Ford, and so far the the CEL has not reappeared.

My engine runs much more smoothly, knocks a whole lot less, and seems a little stronger. I'm going to throw in a new set of plugs, since the current ones have been running hot with the EGR insufficient and have undergone a lot of detonation. The next check is to see what kind of gas mileage I get now (and to get my emissions test for my overdue tabs). At the moment, a couple of celebratory beers.

Thanks for your help- this forum helped me diagnose and resolve this code without running to the local dealership and throwing a good portion of my income into financing their family vacations, kids college funds, etc. I'm telling everyone I know with a Ford truck about this site.

 

Glad it worked out for you.

 

If your CEL comes back on you may want to clean out the SMALL hole at the BOTTOM of the large hole under the EGR.If this port is clogged it will give code 401,mine drove me crazy,,Iwould clear the code then the next day or two it would be on again.I replaced everything EGR related but only cleaning this port fixed it.

 

Vin what port are you talking about? My EGR on a 3.0L Ranger has a large lower port that is coupled to a threaded slip nut for the exhaust outlet. I've cleaned this and the port into the manifold but still get error code 401. I would like to know how to do the IAC/pressure test is someone can help out. Thanks all.

 

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How about the DPFE sensor, have you replaced that? It's often responsible for the 401 code, especially on the 3.0L.