Intermittent EGR problem - is there a sensor inside the EGR valve housing?

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New Member
Apr 10, 2021
Bristol, UK
Mercedes C207 E350
Hi All,

Thanks for looking.
Car runs perfectly fine until it hits normal temperature and then enters reduced power - it's not quite limp mode it still revs over 3000k but there is no turbo boost and very slow to accelerate.
Every now and then when the engine is still hot i'll turn the car off and back on again after going to the shops or something and then it's back!!! full power and turbo, then as soon as I switch it off and on it's gone back to reduced power.

My fault codes are P404 and P405 so most likely the EGR.

I've taken the EGR out and it was nowhere near as bad as some I've seen on line - this car has now done 210,000 miles and this is the original egr so I was actually shocked how relatively clean it was.
Anyway, took it out cleaned it up, took the black plastic cover off and checked the mechanism and it all works smooth. Replace in car and still have exactly the same problem.

Because the egr arm/valve is working smooth inside is there a sensor inside the other top piece that does something? I say this because after where the wiring plug enters the egr, there is melting/melted plastic - so I'm wondering if a chip or something has got fried and then it's not understanding when to open or close the valve.

Has anyone else have experience of an intermittent egr issue? The few lucid moments I get now and again and the car actually drives like a rocket but it only lasts the journey.

I got the exact problem on my w221. I got a new egr valve ordered so hopefully that will sort the problem out
Maybe think about a remap? take the EGR out of the equation?
I got the exact problem on my w221. I got a new egr valve ordered so hopefully that will sort the problem out
UPDATE : About a week later after my post I bought an aftermarket EGR on eBay for £85 and fitted it myself and car is driving amazing again!
:banana:I ordered a aftermarket egr from China for £75 delivered so hope I have same luck as you
😀there's always another job to do. For me i got the front driver speed sensor
Would you guys know if the egr in ML350 bluetec 2013 are merc geniune or they ve installed from other vendor like elstock?

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