My guess is it's low.
Kidding aside, just check the bottle level. Add coolant accordingly. I'm not sure if being a 2001 it takes Green, or GL5 (Gold). I'll check when I get to work.
Regardless, make sure to make a mental notation of when you filled it and with about how much. Then, if the alert ever comes on again, and theres the possibility of a coolant leak, you'll already have an idea how much of a leak you potentially have.