wat should I do and expect now that my emissions system light came on on 2004 Lincoln Navigator

The light just came on last night.......not the check engine light

Asked by for the 2004 Lincoln Navigator
Emissions System light is the same as the check engine light, service engine soon light etc. Many names for the same thing. It takes about 1 hour to determine what the code or codes mean and what the issue is, then you go from there. It can be anything from a bad cat converter ( expensive ) to a worn out gas cap.

here are some shops: