Probably not, but a leaking EGR (stuck partially open) might cause enough of
a problem to fail the test, and not trigger the SES. Been there, done that!

"James1549" > wrote in message
...
> >Check the EGR valve for proper action. IIRC, it controls NOx.
>
> That is my first thought also, but that should trigger the SES light.
>
> Also I am not sure the EGR valve operates at 15 mph.
>
> James