I currently have the same CEL and a scangauge 2, but they are not related. I've had many CELs prior to my SC2. The light came on a week and a half ago, then went out, then came back on and then went out again. I'm watching it before I seek further action.
What's the condition of the flange by your SCR? Several people including myself have significant corrosion with at least two people experiencing broken studs there.