it could be normal...
the position of the egr valve ? stuck at 0% or still working?
I honestly do not know, the customer ? returned today and I was messed up... I have not been able to verify. Anyway, the valve I clean and should be safe to zero, it gives an error in diagnosis, and not me, does it cancel? the light does not turn on immediately, but after traveling a bit.
the light, I believe, does not turn on immediately, because before you turn on the light, the error must occur several times, after which the controller validation is that the error ? this really exists, and then turns on the malfunction indicator light engine