Could possibly be the oxygen sensor (or one of the sensors, if you have two) in the emission control system as well. Those can fail when you start getting near the 100K mark, and you're getting close to 90% of the way there. If you've experienced a decrease in fuel efficiency lately that may be a sign. My Civic has about 93K on it and allegedly wants one. I'm going to run some checks to see if it's a wiring issue first. And read the codes my car's computer spits out to see what else it thinks is wrong. o.o

But as drakegrey says, it's pretty much just a "master alarm" light and there are any number of parameters that might be out of range and cause the computer to activate it. Need to read the code(s) or have them read for you to see exactly what's wrong, barring something glaringly obvious like gascaps, fluid levels, etc.