EGR Flow Malfunction
Super Member
Joined: Nov 2001
Posts: 789
Likes: 55
From: Henrico, Virginia
2014 ML350 4Matic
It is always best to say what car you have. From your profile I assume you are talking about a C36 with the M104 engine. If that is the case it is likely that the end of the EGR tube is plugged where it enters the intake manifold. If you pull off the air pipe from the air filter box to the throttle body and block open the throttle plate, you can insert an inspection mirror with a long handle. The pipe comes in from outboard. It is about 8mm in diameter. You can pick at it with a stiff wire bent to suit. Another option is to disconnect the other end at the EGR valve (on the right rear side of the cylinder head) and try running a cable through the pipe with a drill. Another option is to bend a copper tube into a guide that will go down the intake pipe past the throttle plate and hook back to line up with the end of the EGR pipe. Then you can run a cable down the tube. The EGR pipe can be replaced but it is a very fussy job trying to snake the old one out and the new one in. You will need a scanner to reset the code. If the pipe isn't plugged, you need to troubleshoot the EGR valve and the ccircuit that operates it.
