Isuzu Trooper code p0401

I have an 1997 Isuzu Trooper with a 3.2L and I have the code p0401 egr system insufficient flow detected. I already cleaned all the ports and replaced the EGR valve, I also check all the wiring harness and have no problem but the code is still present. Anyone can help me on this one?

If you actuate the valve with a vacuum pump while the engine is running does it stall? did you clean the ports in the throttle body and the intake?

But this EGR valve is an electrical one, I dont see any vacuum hoses attached to it, if have any where are they located? and I cleaned the ports in the throttle and intake. What other possibilities I have?

how were the ports cleanned? Sometimes the egr port through the intake is so plugged the only way to clean it is remove the intake, What brand of 02 sensor?

might require a scan tool to relearn the egr's position before the code will stay clearred. Might be other posts under your code description that describe how to achieve this without a scan tool

The o2 sensor is the original one, I removed the intake and clean it, and it seems that work out perfect, the code now is not present. I will keep checking for the next few days and let you know.

thanks a lot for the help.

I also have been receiving 401 codes on my 2001 Trooper (86,000) miles. The OBD code refers to insufficient flow on the EGR system. So I did as many others on this board have done, that is replace the EGR unit at $180. Like many others on this board, my 401 code came back as well. So that is when I started to look deeper into the to insufficient flow problem. I was told by 2 professions mechanics that if the EGR value is bad, you will know it. The car will not idle correctly, is difficult to start and runs rough much of the time. My truck did not do any of that. I was also told that in many cases, the insufficient flow may be from carbon in the passageways to and from the EGR valve. After some closer looking with a flashlight in hand, I found a plug that has access to the line between the ERG and the cylinder intake. The plug is located below the EGR unit on the left hand side. You will need a set of hex keys to remove this plug. Once I had the plug removed, I had clear access to the horizontal passageway to the engine intake. I quick inspection did show quite a bit of carbon build up within. To clean the passageway, I broke out my gun cleaning kits and used the barrel brushes attached to a 12 inch section of rod. I believe that it was the .40 caliber brush that was the closest in size. I also used the generic carb cleaner in the process as well. This scrubbing did remove much more buildup than I imagined. I installed the plug back in it’s place and have not had a 401 so far. So I believe that possibly could have been the problem.

The only other item of question in the EGR system is the DPFE value. So far, I have not been able to find the DPFE value on the Trooper, or even confirm that it has one. Any ideas??

it doesn't have one! dpfe is fords genius invention

Dang,, no wonder I cound not find it!!
Thanks for the clarification.

This is probably more than you need to know but I did all the work so maybe someone else can benifit.

Check this link for what I had to do.

http://home.adelphia.net/~pjcalinski/Tr ... perEGR.htm

PeteC