Having lived with the engine management system fault light on for a while it suddenly corrected itself for 48hours then came back up. This has happened a couple of times over the past few months... As far as I can tell the fault clears itself when the ambient air temperature is low (below freezing)... I was wondering if anyone has had a similar problem under similar circumstances and has managed to find out where the problem lies...

 

Already tried cleaning the EGR valve, checked vac pipes between the EGR and monitor sensor.....

 

I suspect that one of the sensors is at fault here (mass air flow, ambient air or some other sensor that may be causing the issue) hope someone can confirm this and suggest which is most likely to be the cause..

 

TIA

 

Grumbee

Had this on my old passat, never caused me any performance issues, just an annoying engine light. I even replaced my EGR and the MAF but it still didn't resolve it. Unfortunately I never got to the bottom of what caused it as it probably needed vagcom, not my autel OBD reader to identify the issue. I always thought it was one of the N valves (N18) in the end, but as it didn't cause me any issues I never bothered getting to bottom of it.

I would love to know what it is on your car?