Code P0402: EGR excessive flow

[vagrantviking]

One day I will go for more than a week without the CEL coming on.

This time around I get the above code saying EGR excessive flow. Seems a bit odd as I would expect problems with the EGR valve to cause it not to open at all. Pulling off the hose and applying a vacuum it looks like the valve is working fine.

Next thing working back would be the N18 valve. I am tempted to just order one up and try it but would rather save the $75 if there is a way to test it first. Maybe swap with the N75?

Looking up general EGR problems I have seen it suggested that the problem is likely the PDFE sensor but I have not found any reference to it on this site. Would like to track it down and test it also before ordering any parts.

Anything else that I should be looking at?

Thanks for any insights.
Viking

[chittychittybangbang]

Yes, start with the n75-n18 swap and see what happens. Maybe wiring? You said you pulled off the hose and it holds vac, next check the the vac lines themselves.