our cars have a Maintenance Required light so its not on to remind you of upcoming service.

for the light being on, there is no way to tell whats wrong unless you get the code(s)read. i would get a code reader(autozone reads codes for free i believe) or jump the 2 pin connect on the right side of the dash next to the glove box(its taped up with a rubber boot on the end of it) and read the codes off the check engine light. the latter is more involved so i would just get my hands on a code reader.