EGR Error Code is Stumping Me
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MBWorld Fanatic!
Joined: May 2015
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From: Allentown, PA
'08 GL 320 CDI
EGR Error Code is Stumping Me
Concerning the exhaust gas recirc valve on the top/rear/driver's side of the engine I'm at a loss to figure this out. I keep getting a code that puts the engine into limp mode. I can clear this while still driving, but it usually comes back within minutes. Luckily, even though the fuel is being quite limited and demanded downshifts are not allowed, I can get by with manual shifting (if needed) because there's still a good amount of power available in the low RPM band. But it's annoying that I can't seem to figure this out 
-- I've removed and cleaned the EGR valve a couple times - it's only ever slightly sooty - very light, actually
-- It physically moves well by my hand
-- A local indy was able to command it to open/close using their computer (it was in the shop for a different reason so they didn't have time to go further)
Is there another sensor for this system that I'm not aware of? My googling for this code keeps coming back to "just replace the EGR". But it seems like the EGR is functioning correctly.
-- I've removed and cleaned the EGR valve a couple times - it's only ever slightly sooty - very light, actually
-- It physically moves well by my hand
-- A local indy was able to command it to open/close using their computer (it was in the shop for a different reason so they didn't have time to go further)
Is there another sensor for this system that I'm not aware of? My googling for this code keeps coming back to "just replace the EGR". But it seems like the EGR is functioning correctly.
Last edited by DennisG01; May 2, 2023 at 01:52 PM.
Thread Starter
MBWorld Fanatic!
Joined: May 2015
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From: Allentown, PA
'08 GL 320 CDI
They're new (relatively, anyways). Installed an oil vapor catch can immediately after putting the new intakes on. But this is definitely an EGR code so something specifically in the EGR system is either wrong or a flaky sensor or bad wiring. It's just strange that the EGR can be successfully commanded by STAR/DAS and it operates as expected. I don't know what else is the EGR system that could be causing this.
Thread Starter
MBWorld Fanatic!
Joined: May 2015
Posts: 1,932
Likes: 291
From: Allentown, PA
'08 GL 320 CDI
Thread Starter
MBWorld Fanatic!
Joined: May 2015
Posts: 1,932
Likes: 291
From: Allentown, PA
'08 GL 320 CDI
Sallad, was there anything else you found along the way in your "investigation" that led you towards the DPF sensor? Do you happen to recall what EGR codes you were getting? I'm just trying to gather as much info as I can here. Thanks!
My DPF sensor isn't all that old.. but odder things have happened!
My DPF sensor isn't all that old.. but odder things have happened!
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Thread Starter
MBWorld Fanatic!
Joined: May 2015
Posts: 1,932
Likes: 291
From: Allentown, PA
'08 GL 320 CDI
I've been driving the car over the last couple days - primarily city (short stints on the highway) and for no more than about 25 minutes at a time. I have full power and it's not going into limp mode.
I suspect that there must be a time or mileage-driven variable that has to be met in order for the EGR to be activated?
I suspect that there must be a time or mileage-driven variable that has to be met in order for the EGR to be activated?
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