Contour Enthusiasts Group Archives Forums General Troubleshooting CEL and P0401

Hi,
I am consistently getting this code from my 98 Mercury mystique. I had this code once before(several months ago), and the autoshop said the egr passage was blocked with carbon, and it was so bad that they have to take the tube out to drill out the carbon deposits. Several months later, the problem returned. Now I am wondering what I should do. I am wondering if this is something that is easy to do for myself, since I don't know much about cars. I will really appreciate if someone can post the instructions (photos too) for fixing the problem. Thanks.

This is a common problem for Contours/Mystiques.

If you search the forums, you will find plenty of posts on CEL P0401.

Unfortunately, there is no simple solution to this problem, since there are many components that make up the EGR system.

Here are some of the reasons for a P0401:
- Vacuum hoses for EGR system are clogged, loose, or have leaks
- EGR (exhaust gas recirculation) valve clogged or stuck
- EVR (EGR vacuum regulator) solenoid is not functioning (i.e., opening) correctly
- DPFE (differential pressure feedback EGR) sensor not functioning correctly
- EGR passage in UIM (upper intake manifold) clogged (you would not drill out this part though)
- EGR pipe (from EGR valve to exhaust manifold) is clogged

Thanks G Pappas,

I searched throughout the forum, and found lots of people having the same problem. Does that mean there is a design flaw in the car? I rarely hear other cars having similar problems with the EGR. Does ford/mercury warranty this flaw to a certain extent?
Since like you said, the problem might lie anywhere in the EGR system, I don't think I will attempt to fix it myself. So what is a fair cost for a shop to diagnostic the problem and fix it? Please let me know. Thanks.

I don't know if I would call it a "design flaw", after all cars don't last forever, but it is a fairly common problem for our cars. I would think that it would fall under the "normal wear and tear" category.

If you are within warranty, then Ford might take care of it, but I'm not sure. Someone else on the boards might know better.

If your out of warranty, then definitely not, unless you recently had the EGR system worked on and the same piece broke again.

Don't have any idea. I don't work in the business, but here is my guesstimate...

If you decided to replace ALL of the major parts (EGR, EVR, DPFE) to the EGR system, then you should be able to buy the parts brand new for around $150. It would take me a few hours to do the labor (and I'm not a professional and don't have power tools). Let's say 3-4 hours on the long side. At $75/hr. (it might be more or less in your area), you would have $300 in labor at the most. Thus, it would cost about $450 for the whole thing.

But the problem is that it might be something else, like the EGR vacuum hoses or the EGR-to-exhaust manifold pipe or even the PCM.

Most of the work is not that difficult to do yourself, it just depends on your ability and your confidence level. You will also need to spend some $ on tools if you don't have them.

Other than that, all I can say is to take the car to a few auto repair shops and get an estimate. Once you get an estimate, post another message with the cost and what they say they will do and you should get at least a few opinions.

its @#$#@ confusing! unless your going to replace every part he just listed.. otherwise your going to go through the pain in the a55 of replacing parts individually that werent really the problem (like I did ) your better off taking it to a dealer who can test each component to find out the true problem.