No expert here, but doesn't it take several run cycles for the computer to clear the CEL?

I also have a ML430, cleaned the EGR tube and P0400 code (and other 4 codes I mentioned earlier) keep coming back after I cleared them. Not sure what to do next, EGR valve? One more thing I noticed, since I have this P0400 (almost a month now), for the first time since I have the car I also got low oil light. I never had to add oil between oil changes ,this is the first time (have about 105K mi). I am wondering if these are related……

SUNEDOG:

Thanks for the additional image. I was able to remove my EGR tube and clean it. I will now in the next few days if it has cured my P0400 code and hot starting issue.

pdf files
 

I would like to receive the PDF files, how do I send you e-mail?

ygpms

I sent you a private message. Click on "Private Messages" in upper right corner after you log on to the forum.

EGR line removal
 

Received a PO400 code on 98 c280. Can anyone tell me the best way to remove the EGR line,or what size is the nut and torx that hold it in place. Found a tool at ZDMAK a little expensive,but not sure of the size of the nut (Crowsfoot Valve Tool).Replies would be greatly appreciated !!

I have this exact car, what I used was a small crescent wrench on the tube nut itself. My line wrenches were to long to fit in place. Also the torx bolt can be removed with a standard 6-point 3/8" I believe. It is the same size as your valve cover bolts if you want use that to size reference.

You will also need to remove the rubber thing pictured to get the EGR tube out. Please note the little "tit" for lack of a better term that goes in to the plenum may break off. I suggest you buy a new one as yours will be very brittle. If part of it breaks off you need to open the butterfly put you hand in there palm facing up and use a small Phillips to push the piece through. Make SURE you catch the piece.

http://farm4.static.flickr.com/3137/...b616d8fa31.jpg

As you can see I have the old and new, you can see where the old one broke off:

http://farm4.static.flickr.com/3287/...5bd0642113.jpg

Now once you get the EGR tube out it will be nice and nasty like this:

http://farm4.static.flickr.com/3187/...9e35906117.jpg
http://farm4.static.flickr.com/3069/...1a4ef410e0.jpg

To clean it I let mine soak in Seafoam Deep Creep over night (PB Blaster will work as well). Then I used a coat hook to clean it out.

If you have any further questions I would be more than happy to help. Click here to email me

Info was right on... But
 

Remove and cleaned Egr line.And as you stated the double nipple (TiT) broke off.Trying to find another one but the search comes up empty.Using the part # A1120180009. If you have any more Info it would be greatly appreciated.Again thanks for the pics and instructions:D

Your local dealer should be able to look it up for you. I couldn't find it online so I went straight to the dealer parts counter. I don't remember how much the part was but it was reasonable (I think it was like $30).

Part Found
 

Tried a few websites came up empty,then called a local Benz dealer got it for 9.05. Thanks again Wizo.

Any time :)

I removed and cleaned out the EGR tube on my 2002 ML320. It had a lot of trash in it but wasn't clogged as bad as these shown. I'd HATE to try to get the one off my ML430.

It isn't too terribly difficult, but it isn't fun either!!

http://www.peachparts.com/shopforum/ml-gl-g-wagen-r-class-unimog-sprinter/335489-egr-flow-issue-p0400-01-ml430.html

Hi, I think I may be faced with the same situation. I have checked voltage and resistance on electrical part of EGR valve. Also, from what I understand applying vacuum to a working EGR valve should cause the engine to stall.
Vacuum to EGR has no affect and voltage measures 6.64v resistance is 0.34. I don't know what affects voltage and resistance.