Originally Posted by J08M3
They have no effect on emissions tuning but they have 100% effect on passing a readiness test for an inspection. If you turn them off you fail. If you clear the code right before test they don't show as ready and you fail.
I agree, but if HC & NOx are above passing levels in the first place, a light isn't going to help at all.
It's going about it a bit backwards since the visual is performed first - but I'm trying to look at the entire situation rather than focusing on one specific portion.