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2355-002: EGR Control Air Mass Too High

55K views 6 replies 3 participants last post by  W245207  
#1 ·
B180CDi 2005 85,000 miles:

The car had rough idle, like 'huffing' sound. My understanding was this could be a leaky injector seal as it's common with Mercedes diesels. However, on removing the injector well and to my suprise it was clean like from factory. There were no codes present apart from the parking sensors.

Although, the egr valve was clean, I did also superficially clean the mixing chamber with brush. On asssembly, now I get the above code 2355-2 with engine check light, but idle is stable and there's no 'huffing' sound.

So I decided to strip and clean the mixing chamber, throttle and the intake port.

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The code is still present :mad:. The vacuum pipes have been changed and both pressure converters are new. I have tested the egr valve with a vacuum pump and opens fine, however the valve is slightly sticky when releasing vacuum. Furthermore, at the time I should have checked the egr pipe to the cooler for blockage :rolleyes:. The rough idle I believe is related to the intake flaps or the motor since it's heavily coked up with carbon.

I also noticed, the vacuum lines to the vacuum tank in the air filter box were broken :mad: so I replaced the air filter box.

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Before I throw money towards a new egr valve, I would love to clean the intake manifold and flaps. Not sure if this is possible without dropping the engine.
 
#2 ·
A rough idle due to the EGR system means exhaust is still making its way to the intake due to a bad sealing at the EGR valve due to carbon deposits. Focus on the area where the valve closes against the exhaust passage. Can you get in there and clean it better?
 
#3 ·
When it's idling rough, the egr duty cycle is at 95%. However, with 2355-2 code the egr duty cycle is at 5%. This is pretty much similar to what Dave2302 experienced with the sprinter.

The valve is clean, and other bits are pretty spotless. Looking around on other forums, the issue is most likely related with the intake flaps (#120)

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#7 · (Edited)
UPDATE [Solved]:

A few weeks ago I replaced the EGR valve which didn't make any difference. However, I replaced the plastic Y branch fitting with a new rubber version (A6030780045)

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This seems to have solved the 2355-2 code and I'm getting boost now. On closer inspection of the old Y connector, there is a fine crack on both openings.

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