Contour Enthusiasts Group Archives

  I take it that this DTC indicates that the EGR valve is not closing as far as it should?  I suppose that some weekend in the near future, I will have to remove the EGR valve, and either repair or replace it.  What should I expect to find?  Is it likely that this is a matter of just needing to clean and/or lubricate it, or should I plan on replacing it.

  I've noticed recent discussions about EGR valves being dirty and clogged, and the symtoms which this creates; it looks like I have rather an opposite condition here.  Other than causing the CEL to come on from time to time, what other symptoms is this condition likely to produce?

  Anyone got some useful insight, wisdom, or advice to share on this subject?

  This is, by the way, with regard to my 1996 Mystique, described in my .sig block.

I ran a scan tool and it came up the same, but it ended up being the O2 sensor that needed to be replaced. But I do know of many EGR valve problems like you have described. Just thought I would give you my.02 on a similar situation.

SVT Contour 3 wrote:

I ran a scan tool and it came up the same, but it ended up being the O2 sensor that needed to be replaced. But I do know of many EGR valve problems like you have described. Just thought I would give you my .02 on a similar situation.

  So I should probably have a good look at the EGR valve, and if I find no sign of any problem with it, perhaps I should consider the O2 sensors.

  Then again, I think I have some evidence to the effect that it isn't the O2 sensors.

  The CEL has only gone from being off to being on shortly after starting the engine, and often when the engine has been cold.  I believe that the O2 sensors need time to get up to temperature before they can be expected to work, so there's no reason for the PCM expect them to work when the engine has just been cold-started, and so it should not, at that point, ever set an error on account of them. Am I right about this?

  Sifting through some data I collected while playing with my new OBD-II stuff, I have found something else which might be relevant.  Near the end of my tinkering, I had cleared out the DTC, I had cleared out all the stored data on my laptop from the previous runs of the OBD-2 system, started it all up, and took the car for a drive.  Somewhere in the course of this, I also ran the tests on the TEST tab, and the results from these were stored.  Looking over these results, I see that two of the tests failed.  One was the EGRDHHDIS test, which is consistent with the P0402 code in that it indicates that there was much more pressure or flow than there should have been through the EGR system.  The other failed test is the CATRAT2 test, which seems to indicate a problem with the second catalytic converter.  I'm very hazy on just how the EGR system works, but it seems conceivable that if the catalytic converters are in any way obstructed, it would increase the back pressure, which might increase the flow through the EGR valve.  I'm wondering if there's a possibility that there's some other interaction, in the other direction, where a problem with the EGR system could cause the cat to operate below par.

  Anyway, just in case anyone else who has the OBD-2 software wants to look at this data and tell me what you think it means, I've put it up for downloading at <http://www.impulse.net/~blaylock/96Mstq.zip>; just unZip it, load it into the software, run it, and look at the TEST tab.

I am in the market for OBDII software and cables. How do you like the kit you have?

That sounds like a very reasonable explanation. What year is your car? If its 96 or older, I would definitely suspect a clogged cat.

I've got the obd-2 scanner and software on order, and should have it either Saturday or Monday. Actually, I have the software license number already if I want to download it, so I guess I can read your data without the actual hardware. So I guess e-mail me your file, and I'll take a look.


sting45470@yahoo.com

Replace the EGR valve! I just did this on my car, same code.
-Mark

GalaxyEng wrote:

I am in the market for OBDII software and cables. How do you like the kit you have?

  So far, I am favourably impressed with it.

stingray454 wrote:

That sounds like a very reasonable explanation. What year is your car? If its 96 or older, I would definitely suspect a clogged cat.

  It's a 1996, with about 121,000 miles on it.

I've got the obd-2 scanner and software on order, and should have it either Saturday or Monday. Actually, I have the software license number already if I want to download it, so I guess I can read your data without the actual hardware. So I guess e-mail me your file, and I'll take a look.

  You only need the code to have it talk to the hardware interface.  Even without the code, you can still use it to analyze files recorded by others.

  My file is at <http://www.impulse.net/~blaylock/96Mstq.zip>.

  So, how bad is it gonna be to get this cat fixed, if that's the problem?  Is this anything I can think of doing myself, or does this need to go to a shop that does exhaust work?  What's a new cat gonna cost me?  Any chance I can clean out the old cat in some way, perhaps by blowing clean air through it backwards?

I have the software, and I loaded your file. I'm new at this, so I don't know what I'm doing yet. I figured out how to replay everything. I see 2 fail codes in the test tab, both called MANUDEF with a CID of $21. I have no idea what any of this means, and the software doesn't explain anything. Since I don't have my car's data yet to compare it too, its tough for me to comment.

There was a known issue with defective cat converters on 95's and 96's where the catalyst material would disintegrate and plug up. I had this happen to my '96 at 40k miles. They were covered under the federal emissions warranty and all three cats were replaced for free. Your mileage puts you out of that warranty however. You have a Zetec, so it may be easier to replace. There should be 2 cats on your car - a precat next to the exhaust manifold, and the main cat under the car. Both should be replaced. Figure about $500 in parts if you do it yourself. Add in another $200 if you have a dealer or mechanic do it for you. I know, they're not cheap. On the V-6 its a major PITA job because both manifolds need to be replaced and there's no room to work. Glad I didn't have to do it.