Just to clarify, the car was diagnosed where I used to live two years ago by a competent Mercedes mechanic. The catalytic converter was rattling (the noise is now gone) since I bought the car (with 75,000 miles on it). The CEL would come and go over the last two years, but has stayed on constantly for the past 3 months, so I thought it was time to fix the previously diagnosed problem. The local Mercedes dealer installed the cat the other day and offered no other explanations (they were short staffed for the holidays), except to tell me that P0422 was NOT the converter and installing the new converter would not clear the CEL.

I do not enjoy spending money to just "part replace," especially with the cost of Mercedes parts and most especially if replacement is not needed. It is difficult to find a competent Mercedes mechanic where I live. The shop I had found was severely damaged by hurricane Ivan and was not open. While I appreciate suggestions and comments, I thought this forum was for Mercedes owners to find help, not get lectured. I don't believe I have ever claimed to be a mechanic. I have enjoyed fixing minor issues and doing scheduled maintenance over the years on all of my cars. Again, I appreciate suggestions, but I can say that I have never been lectured on any of the Acura and BMW forums I have followed and posted on over the years.

SEE, I even "warned" you to NOT take this the wrong way! I wasn't aiming this comment at anyone in particular, just a warning that a code can be interpreted the wrong way if you're not careful.

Gilly

jford,
If I have offended, or lectured to you, I apologize.
Not my intent, whatsoever.
I don't think Gilly was trying to lecture you, either.
He specifically stated this in his comment above.

I, like you, am not a Mercedes mechanic.
I do, however, work with a few of the best in the business,IMHO,
and procure for them the parts needed for them to do their job.
I have done this for the last 15 years, and like to think I have learned a thing or two along the way. I also handle a large portion of the customer write-up and service advisor duties in our shop.

If the cat was rattling, then it was no good. Period.
However, there may very well be an additonal fault.
I am surprised a M-B dealer would install an aftermarket cat.
I know no local dealer would, but that may be due to emissions testing.
We have had problems with the aftermarket cats.
I will not cite engine management or OBD-II theory here, as I am not
capable. I will leave that to Steve B. and others more qualified.

I have no problem with you handling minor issues and maintenance on your own, and, in addition, whatever level of mechanical work with which you are comfortable.
I think it's great, and what this forum is about.

You asked for help, and I tried to help.
Gilly offered a possible item to be checked further.
I am curious as to what response you may have found more helpful?

Tx Benz: Your response has been the most helpful to my situation. I appreciate your insights. I was referring to Gilly....warning or not, Gilly was lecturing. Giving someone a warning not to be offended about something means you know you are about to offend someone, but you do it anyway.

Well,
I read this a dozen times and all I see from Gilly is an " Et Al" Post Script
to your thread .
And it's content is a simple information message making the readers aware of the mis-interpretation of codes and their association with incorrect part changes .
Quite common, and one should thank him for pointing this out.....

Mmmm, not always. I just knew that it would be possible for "someone" to jump to the conclusion that they were being accused of being a parts replacer at best and at worst have really strange ideas about the proper maintenance and repair of automobiles in general and Mercedes-Benz in particular, are a little too fast to judge, are confrontational and unappreciative and smell "funny". Oh wait, I did warn you to not take this thread the wrong way either, didn't I? Dork.

Gilly

Well, gee Gilly, I guess I should blame the original mechanic for the diagnosis and RPM55 for confirming the meaning of the code (not to mention the cat rattling, indicating that it needed to be replaced.) It never ceases to amaze me that some people feel the need to be so condescending on a forum where people are looking for a little assistance.

As long as you have someone to blame, it's OK.

Gilly

Gilly

Even if you don't play hockey, I think you should get one of those plastic " cups " to wear.
Seems to me some people really enjoy kicking you in the balls. :rolleyes:

Yeah no shixt, glad you noticed.

Gilly