Codes P0400 and P0411 in Benz

[wirelessF]

Check engine light came on in uncles MB and hooked up code scanner and popped up codes P0400 and P0411.

P0400: Exhaust Gas Recirculation Flow Malfunction
P0411: Sec.Air Inj. Sys. Incorrect Flow Detected

I checked on several MB forums and it could be clogged passages. Or could it be something else? I don't want to start throwing parts at it.

 

[StevieC]

Probably clogged passages. Take the EGR off and have a look. Not sure if your EGR is fully electronic or Vacuum driven. Being a Benz I would imagine it would be electronic and expensive to replace.

Take it off and have a look first. If not it could be the flow sensor that is the problem.

Is there a way that you can apply voltage/vacuum to make the EGR operate at idle? If so, if the car studders/stalls out the EGR itself is good and it leaves clogged passages or a flow sensor that is the problem.

Good luck...