Most modern cars occasionally show the orange engine management / emissions light. The extreme weather conditions can be a cause, particularly when a cold spell ends and condensation ends up where it shouldn't, a little rough idling is quite common on start up. If you have only had the orange light (NOT red) and the light doesn't reappear when restarting then you don't need a dealer visit in my opinion. Keep an eye on the issue and see if it happens after some particular sequence of events (several days without use, drop in temperature, thaw after a cold spell....) which could help future diagnosis.

Steven Quas , Hamburg