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I had an issues on my Vehicle W212 E300 M272 Engine with the error code in details below:
0745: Mixture too lean bank 1
0749: Mixture too lean bank 2
I already replaced both downstream O2 sensor since the value is not balanced between each other, attached the value before replaced:
After replacing both sensor, the value is balanced but the check engine returned with the same issues and error codes.
Also I already replaced the breather hose with part number A2720181382.
The vehicle doesn't show the weird symptoms the idle is smooth not rough, however the idle feels more shaky during the cold start and it feels maybe around 30 seconds and the rough idle is gone when the idle going down into 600-700rpm.
First thing i'd do is remove the air filter box and inspect all the gaskets. the one at the elbow to throttle body, maf to elbow, air box seal. I replaced my air box seal because it looked worn, after replacing it the box fit on tighter and the metal clip snapped on over the top much better where before it felt loose.
I had an issues on my Vehicle W212 E300 M272 Engine with the error code in details below:
0745: Mixture too lean bank 1
0749: Mixture too lean bank 2
I already replaced both downstream O2 sensor since the value is not balanced between each other, attached the value before replaced:
After replacing both sensor, the value is balanced but the check engine returned with the same issues and error codes.
Also I already replaced the breather hose with part number A2720181382.
The vehicle doesn't show the weird symptoms the idle is smooth not rough, however the idle feels more shaky during the cold start and it feels maybe around 30 seconds and the rough idle is gone when the idle going down into 600-700rpm.
Need your advice and guide.
Thank you all
I don't know who guessed downstream sensors as a solution for this.... UPSTREAM perhaps but not without diagnosis first.
You have two lean banks faults... read the fuel pressure under load: stable or low??
this is similar to my issues and I have yet to solve the imbalance between bank 1 and bank 2 )
However, I managed to decrease the fuel trim by replacing several parts, which related to combustion and vacuum (leaks)
btw, what is your fuel trim figures? or self adjjustment in idle speed range, in both bank? and also self-adjustment in upper partial load range, both banks. (can bee seen in xentry or launch mb scanner).
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