S500 check engine light ERG valve
 

I keep getting the check engine light i pulled the codes and i get EGR valve it seens to be working i tested with a vacum tester and valves opens and its clean can any one point me in the right direction on what to look for? or how to solve the
problem? the car is 94 S500 199900 miles

. . have you checked the
 

EGR switchover valve (Y27) or maybe the check valve (128) that drives the EGR valve (B9)?

Check my page, menu #1, look at the block diagram. Y27 and 128 valve are behind the right head light.

thanks i will check the valves

Make sure the line from the egr valve to the intake manifold is clear.

The biggest problem is the vacuum supply from the swithing valve to the EGR valve. They break if the engine mounts are worn or replaced.....Check this first!