richardhunter1
Citan diesel boost issue diagnosis
Summary of the thread
A 2013 Mercedes Citan diesel is experiencing boost issues, with symptoms including a check engine light, reduced power, sluggish engine response, occasional stalling, increased fuel consumption, and a whistling noise turning into a loud hiss during acceleration. The initial suspicion was a wastegate valve problem, but a faulty pressure sensor was also considered. After further investigation and a workshop visit, it was confirmed that the wastegate valve was defective, leading to the resolution of the issue.
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4 comment(s)
richardhunter1 (community.author)
I appreciate the input I did a visual inspection of the hoses but I didn't find anything obvious How did you ultimately diagnose the wastegate problem on your Megane Was it throwing specific codes or did you have to do more in-depth testing to confirm it I'm trying to avoid just throwing parts at it but the symptoms are getting worse
manuellehmann6
The Megane was throwing a 'turbo underboost' code but the mechanic also noticed the wastegate actuator arm was sticking He disconnected the arm and could feel the resistance It sounds like you are experiencing something similar Given your symptoms I'd suggest getting it checked out at a workshop They can pressure test the system and properly diagnose the problem Could save you money in the long run
richardhunter1 (community.author)
Thanks for the insight I took it to a workshop and they confirmed the wastegate valve was defective The total repair cost was 860€ Appreciate your help in narrowing down the possibilities
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MERCEDES
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CITAN
manuellehmann6
Those symptoms do sound like a boost leak or wastegate issue I had similar problems on my old Renault Megane though it was a petrol engine Reduced power check engine light and a whistling sound were the main culprits Have you checked for any obvious cracks or leaks in the hoses connected to the turbo A split hose can cause all sorts of boost-related problems It could also be the pressure sensor giving false readings but my bet is on the wastegate sticking Did you notice any turbo lag before this started