[Zhawk]

Yeah, the light could have easily been caused by the missing filter and open lid. The sensor in the air ducting is pretty sensitive to how much air flows through there.
Put in a new filter and clear the light. (If you don't have a code reader then most major parts stores will read the codes and clear the light for free.) After that see if the light comes back on.

I doubt your throttle body has any damage and you probably didn't suck anything into your intake. So, just try what I suggested and keep an eye on things.

Good luck and keep us informed.