robertsteel1
Mercedes Citan Diesel Engine Fault
Summary of the thread
A 2022 Mercedes Citan diesel with 263,925 km developed a fault, indicated by a check engine light, loss of power, increased fuel consumption, smoke during acceleration, and a rough-running engine. The symptoms, including a loud hissing sound, suggested a potential issue with the EGR valve, possibly due to a leak or it being stuck open. The EGR valve's malfunction can disrupt the air/fuel mixture, especially when the engine is cold, leading to rough idling. The problem was confirmed by a workshop, and the EGR valve was replaced to resolve the issue.
Did this summary help you solve your problem?
4 comment(s)
robertsteel1 (community.author)
The rough running seems to be worse when the engine is cold, yes. What exactly does the EGR valve do anyway? And is it a big job to replace?
melina_koch10
The EGR valve recirculates exhaust gases back into the engine to reduce emissions. If it's stuck open, especially when cold, it messes with the air/fuel mixture and causes a rough idle. Replacing it isn't usually a massive job, but it can be fiddly, and you might need some specialized tools. Given the symptoms and mileage, I'd suggest getting it checked out by a workshop. They can confirm the EGR valve is the issue and give you a proper quote for repair.
robertsteel1 (community.author)
Thanks for the advice. I took it to a workshop, and they confirmed it was the EGR valve. The total automotive repair cost was 355€. Hopefully, this will fix the problem. Thanks again!
rmh_community_comment_box_header
community_crosslink_scanner_headline
community_crosslink_scanner_intro
community_crosslink_scanner_title
community_crosslink_scanner_price
community_crosslink_rmh_headline
community_crosslink_rmh_intro
community_crosslink_rmh_title
community_crosslink_rmh_subtitle
community_crosslink_rmh_brand
MERCEDES
community_crosslink_rmh_model
CITAN
melina_koch10
Sounds like a dodgy EGR valve to me. The hissing points to a possible leak in the EGR system, which would definitely cause those symptoms. Is the rough idle all the time, or just when the engine is cold? A jammed EGR can cause havoc with your engine's recirculation. Think of it like trying to breathe through a clogged straw. Is it worse when the engine is cold or warmed up?