[Ovi]

My GL 320 CDI went into a limp mode with a check engine light on. I checked the code and it came back as P1402 - possible EGR valve issue.
A new valve is about $350 while a MB dealer replacement goes to about $750.
I took the valve apart and I cleaned it. Everything works perfect.
The valve is located all the way in the back near the fire wall on the driver side. To access it you have to remove the top side of the protective wall. remove both electrical connector before attempting to remove the two screws. After the screws are removed easily pry the valve open with a mechanical flat heat screw driver.
The valve has two small cooling hoses attached at the bottom that distribute engine coolant to the EGR valve body.
Once the valve is out take all the plastic covers out, measure the coil and clean the carbon built up while making sure the spring loaded mechanism works.
Pictures attached.

 

[SkippyJasper]

Nice thread. How many miles?
Skippy

 

[Ovi]

94000 miles.

 

[SkippyJasper]

Anything in particular that led you to the egr valve?

 

[Ovi]

Just through troubleshooting - the P1402 code which is a generic code indeed. I am not very versed into this but I did a lot of research. If it would not be the EGR valve, I would go probably for the DPF sensor located as I understood under the car.

When the fault appeared I reset it first and then I followed up to see when it will reappear again. It took half a day about 50 miles and it came back. I put this post together because I could not find anything online about removing or addressing the EGR valves for MLs or GLs. I found something about E class and that was about it.

No threads tell you that those two little hoses have actually coolant in them. I went to Mercedes dealer in Annapolis because I had the feeling that one of the hoses was pinched. The guy there spent 45 minutes with me and kept asking me if I am sure those hoses (which I had with me, so I showed them to him) are coming from the EGR valve and not from the radiator. Nonetheless he said he could not find them.

So I went to Autozone and bought two feet of rubber hose - and I replaced both of them for $3.95 but that was just to make sure that I have no leaks; that did not have anything to do with the previous fault. So now I have about 500 miles after the repair it seems to hold and I learned at least how to remove the valve .

Ovi

 

[SkippyJasper]

I have two OM642's and likewise have done considerable research into the generic codes presented with non-Star diagnostics.

In my '08 it was the differential pressure sensor that was the culprit and it resides just aft of the transmission in the 'hump'. Lucky guess on my part.

In my '07 with similar limp home modes and the EGR DTC I again replaced the sensor but that did not cure the problem. Dealer found it to be a failing turbo actuator which is a tad more costly than the sensor.

In other threads (Sprinter and MB) what you've done will work for a while presuming that is the problem. What occurs in the EGR valve as far as I can tell is that the electronics begin to fail. The cleaning relief time period will grow shorter until it is evident that the valve is toast.
For some it's an annual thing, others less so.

I haven't picked up on any discernible trend. Appears to vary according to use, climate, oil used, etc.

Skippy

 

[Ovi]

Very interesting posting..I have an E 320 CDI 2006 with no issues whatsoever and I have 104000 miles on it but the SUVs or trucks seemed to be plagued.
In this case I went after the EGR and I am holding my breath. In regards to electronics I am not sure what other components are on that "head" but there is definitely a coil that needs to be checked. I am attaching more pictures.
Anyway please keep posting about your issues because I am sure I will put them to use on my GL. It is just a nice Teutonic car and nothing more.

Now on the way the guys are troubleshooting in these MB shops... If I have something critical I go 70 miles west to Hagerstown and not to my closest MB dealer because I have more trust in them.
There is a tendency in the industry, and I am not referring here just to the auto industry, to replace whatever it is easier and put you on the road. If it does not work you will come back and take it further. Very few technicians do troubleshoot and in a way it is understandable because they are under pressure to deliver and turn around profit quick.

I will keep you posted if the fault comes back.

Ovi

 

[SkippyJasper]

Nice photos and work.
I understand that some/most of the failed EGR's were due to soot getting into the actuating portion of the valve (the part under the plastic that you have exposed). Some grunge is to be expected. Yours looks very clean.

I have 100K on the '07 E and 114K on the '08 ML.

Skippy

 

[Ovi]

Just to follow up...After a while (less tan a 1000 miles) a new code was thrown up, P0471. The next step I have replaced the DPF sensor located under the car on the passenger side. It worked for while and then the fault came back. The next step I replaced the exhaust back pressure sensor and finally I nailed it. No more issues for few months now. I took a trip to Toronto where I ran the car to the max up to 95 mph where possible; no issues whatsoever.
Nevertheless, people from Mercedes told me that if this sensor and EGR valve saga continues the best option is to take the air intake out, soak it well for a day or too and then clean it. That would take care of all the sooth issues according to them.

 

[SkippyJasper]

Thanks for the follow-up.

 

[hamada128]

Thanks for the follow-up.

X 2.