EGR - Oxygen Sensor (Check Enigine Light)

[NowakFilip]

Hello Guys,
I have a problem with my Mercedes Ml 430.
I have replaced new oxygen sensors and EGR. After I have replaced it the check engine light still didn't go off. After I have cleared the codes and start the engine, the check engine light doesn't come on. But when you start the car again the check engine will come up online after three miles.

Please help...
Thank you.

[MADSLEG]

I have almost same problem
I replaced EGR valve and cleaned egr tube-cleared the codes and start the engine, the check engine light doesn't come on. Next morning i got it back with OBD codes 171,173 and 400...........same as before i replaced EGR (((((

[Michael Pillay]

What are the exact codes?

[busoptr]

did you put oem 02 sensors or universal?

[43sqd]

Originally Posted by NowakFilip

Hello Guys,
I have a problem with my Mercedes Ml 430.
I have replaced new oxygen sensors and EGR. After I have replaced it the check engine light still didn't go off. After I have cleared the codes and start the engine, the check engine light doesn't come on. But when you start the car again the check engine will come up online after three miles.

Please help...
Thank you.

We won't be able to help you without posting the codes.

[43sqd]

Originally Posted by MADSLEG

I have almost same problem
I replaced EGR valve and cleaned egr tube-cleared the codes and start the engine, the check engine light doesn't come on. Next morning i got it back with OBD codes 171,173 and 400...........same as before i replaced EGR (((((

Code P0400 means that there is a flow problem in the EGR system, not the EGR valve. You said that you cleaned the EGR tube, but did you remove it and look at the other end of the tube. That is where all of the clogging occurs, and if it is clogged, which it probably is, you will have to remove the throttle body and clean that too.

Another member, CLEARCHRIS, had the same exact problem. Check out this thread and the posts that follow.

http://www.benzworld.org/forums/w163...ight=egr+valve

This is what a clogged EGR tube look like.

http://www.benzworld.org/forums/atta...00525009am.jpg

[MADSLEG]

Originally Posted by 43sqd

This is what a clogged EGR tube look like.

http://www.benzworld.org/forums/atta...00525009am.jpg

Just like my when i pulled it out ))
Then i cleaned it with many many cleaners and only Purple Power was able to take that gunk off.

[43sqd]

Originally Posted by MADSLEG

Just like my when i pulled it out ))
Then i cleaned it with many many cleaners and only Purple Power was able to take that gunk off.

The next step is to remove the throttle body and clean that.

[MADSLEG]

I looked at the throttle body today and i dont think i can remove it,too many bolts ((

[43sqd]

Originally Posted by MADSLEG

I looked at the throttle body today and i dont think i can remove it,too many bolts ((

There are only four bolts that hold the TB on.