codes cleared finally on my VDP, I had P0191 and P0194 constantly coming back no matter what I did. A mechanic friend took a look and listen (I'm pretty much deaf)and heard a whistling air noise. we found 2 o rings old cracked and leaking. we replaced them and the codes all cleared. the rings were on the PVC valve that were leaking. Just in case any of you encounter the same and can't get it figured out. Now on to the CATS SYSTEM FAULT Hahaha. But she really is running great now.

 

Gunny,

You may have mistakenly posted this on the wrong section of the forum, this is the 1998-2003 X308 section, you were maybe looking for the 2004-2009 X350/358 section.

 

I believe you meant to say the codes were P0171 & P0174 bank 1 & 2 lean codes. I know exactly what PCV valve you mean. I hate to tell you but, that valve is actually a controlled air leak. In other words it’s supposed to have air leaking from it, true story. Cleaning the MAF sensor is the first thing and the second is to throughly inspect the air intake pipe from your air box to your throttle body for any cracks in that air baffle. There are many other things that can cause the 171/174 codes but, that’s just a start.

 

pretty sure it’s not supposed to leak at the valve cover just dump to the throttle body

it will always make noise because the hose is a thin piece of plastic