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

1 answer
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: