Felix87

Hello Guys, I know it has been discussed and I have done my research but I need some more help.

I got the famous Bank1 lean code. p0171 I have replaced the purge valve and the oxygen sensor. Of course I am still getting the same code. I have performed a smoke test and everything looked to be good and sealed. When I purchased my car, one of the first maintenance things I did was the K&N filter. When I was changing them I already noticed that my charcoals were gone (most likely by previous owner) I am tuned and have been for couple thousand of miles and never thad this code come back during or after the tune.

What's my next best step, trying to replace the Intake Manifold Gasket? Mass Air Flow Sensor? I'm getting a little tired of replacing pointless parts that are perfectly good. I am not planning on going to the dealer, so I am trying to find the actual resolution.

09 C63 around 45k+ miles.

Thank You For all help.

tfthach13

I can't say for definite, but the MY09 tend to have very sensitive MAF sensors. I've tried every possible combination with dry/oil/stock filters, charcoal delete/charcoals in, re-flashing back to stock/re-uploading tune, cleaned MAFs, etc. And the CEL will always manage to come back on.

Your best bet is to go back to stock paper filters and charcoals in to be rid of the CEL.

Felix87

Before I go spending w.e the amount is for OEM MAF sensors I wanna know that its them for sure. I can't even put the charcoals back in since I have never had them in my possession. I think I am going to try doing the intake manifold gasket and paper filters.

Unless someone can recommend a better option to go about...