what does it mean when I'm driving in my service engine light comes on

It means something is triggering the service light that could be hurting you engine, electric, etc. If you go to "AutoZone" they will plug in a computer and read the code for you so can narrow your search for an answer to why it came on and how to fix it. It only takes 3 min for them to do this, and you don't need to lift the car up or move it. They plug it in right where you parked it.

Bad exhaust sensor. around $50.00 for part.