Nissan Xterra Forum : “My '04 xterra has 49,155 miles on it and the check engine light came on, is that...”

Most likely not.  The manufacturers (Mazda for one) used to do this, where a light would come on for a service, but with the advent of OBD-II diagnostics in 1996, the Check Engine light typically signals sensor or fuel economy issues.  You should have this checked to find out what is causing it so you can correct the problem.

thank you