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.
The code is still present
. 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
. 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
so I replaced the air filter box.
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.