Persistent P0068 (and P061A) on W204 C250 CGI
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From: Warsaw, Poland
W204 C250 1.8CGI
Persistent P0068 (and P061A) on W204 C250 CGI
Hi everyone,
I’m dealing with a persistent P0068 fault on my Mercedes W204 C250 CGI (M271 EVO turbo petrol engine), sometimes accompanied by P061A.
The code usually appears when lifting off the throttle or gently decelerating, not during acceleration.
I’ve already checked the following:
However, there’s a large pressure difference between the MAP sensor and the pressure sensor before the turbo, especially during throttle transitions and deceleration.
I’ve attached live data logs from a few runs showing this mismatch (Xtool)
Could this pressure imbalance be caused by:
Has anyone experienced similar P0068 or P061A behavior on this engine, and found the root cause?
Any insight or shared experience would be really appreciated.
Thanks!
I’m dealing with a persistent P0068 fault on my Mercedes W204 C250 CGI (M271 EVO turbo petrol engine), sometimes accompanied by P061A.
The code usually appears when lifting off the throttle or gently decelerating, not during acceleration.
I’ve already checked the following:
- No intake leaks – smoke test performed, system is completely sealed.
- Throttle body looks clean and reacts properly (around 15° opening right after startup).
- MAP sensor (B28/15) readings seem stable and logical.
- MAF values follow expected airflow under load.
However, there’s a large pressure difference between the MAP sensor and the pressure sensor before the turbo, especially during throttle transitions and deceleration.
I’ve attached live data logs from a few runs showing this mismatch (Xtool)
Could this pressure imbalance be caused by:
- a faulty PCV/valve cover diaphragm,
- a throttle adaptation issue, or
- possibly an ECU calibration problem (I’ve read some M271 EVOs had updates related to load calculation)?
Has anyone experienced similar P0068 or P061A behavior on this engine, and found the root cause?
Any insight or shared experience would be really appreciated.
Thanks!
