scoobytc

Hi guys, i'm sure this has been covered before but i keep getting the engine light on despite a new air pump fitted and replacement changeover valve but my question is, does anyone have a diagram of exactly how and where the change over valve plumbs into as I think maybe I have a hose missing or have missed a connection somewhere. I have trawled the net but can find no diagrams. The car is a W204 C63 M156 engine and i just need a clear picture of where everything goes.
On the change over valve there are 2 stems a thicker one and a thinner one. Which stem is the vacuum to the maniford? thick or thin? I know one of the stems is the vacuum to the check valves I just think I may have them round the wrong way

Mort

Here are some pics from AllDataDIY. Did they help with hose locations? Also did you check to see if the passages in the heads are clear?

scoobytc

Thank you ever so much for those pics, they have helped me greatly. I did pop out again at lunchtime and have a little look again and i wiggled the big pipe that runs from the secondary air pump to the check valves and the CEL went out so I am thinking there may be a split in that pipe. I will remove it at the weekend to inspect but thanks again for your help