About a week ago my check engine light came on and we pulled the code and my son turned it off. Everything seemed ok for a week then this morning I get the same code EGR Flow Malfunction. I have an extended warranty, car has NW dual CAI and Magnaflow cat back. Does the EGR have anything to do with those two things? We think not want to see what you guys think. I should add the car seems to run fine.

 

not sure but here is the mercedes code for po400 ,, P0400 Exhaust Gas Recirculation Flow Malfunction jim

 

would that be related to the gas cap being loose??????

 

No that one ( the gas cap) got me a long time ago. Hopefully the dealer will just replace the EGR valve and I will be on my way. Apparently it can get clogged. I checked all the vacuum lines and nothing seems to be loose or leaking. Thanks AMX we have a really nice MATCO code reader and the corresponding code book, just wondering if anyone knows or has had experience with this particular code. I see a lot of codes semi related, close to but not this one.

 

Yes, I would say that the dealer would probably replace the EGR along with cleaning the throttle body front and back.

 

Exactly what I'm thinking bmorgan. I read a few posts over on the MB Forum and its either the EGR or crud in the lines going into it. I only have 14k on the car so I'm leaning towards a bad EGR valve, guess we will see. Will post once its fixed. Thanks

 

That (EGR) should be covered under your emissions warrentee.

 

Well it was the EGR valve. Dealer had to order it with the gaskets. They tell me it is not an emissions covered part, it is covered by my extended warranty though.

 

That is good to hear. Did they clean the TB while they were at it?

 

 

I am not sure if it is necessary. I was just going by information that I have read on the MB forums. From what I was reading, I took it that a dirty TB could be the cause of the problem with the EGR valve. It would not hurt to ask.

 

I saw that over on the MB forum. I think those cars all had over 100k miles on them and yes that line was caked with carbon. My car only has 14k on it and when I installed my cold air I cleaned that area and nothing, it was pretty darn clean. Now that line may be clogged but I guess they will eliminate that with the valve. If it still pulls the code then that's really all that's left. Thanks for your thoughts, I'll post the final result. the guy who runs the shop is a friend of mine so I'm sure he will take care of me, my wait this morning was like 15 minutes. he's the service mgr. and he personally wheeled out their computer and hooked it up to the car in the lane so I didn't have to wait. Funny thing is the car really feels like it is running strong??? No rough idle or anything.

 

A follow up. My dealer replaced the faulty EGR valve today, light is gone and all is well. Was covered 100% under the emissions warranty.
Pat