MIL Warning Lite

My 2001 Jeep Cherokee's MIL light just popped on.  There doesn't seem anything wrong.  It runs just fine.  Can't figure out what to do!  Any items where I should start and end? Thanks a $$$.

check oxygen sensors, that will be your problem, or maybe catylitic converters, but start with O2 sensors

check your gas cap; a loose or fautly cap is the most common cause of a light. Go to your local autozone; they can read the code and at least narrow it down and put you on the right track.Life moves pretty fast; if you don't stop and look around once in a while; you could miss it.

Overfilling your tank will pop one on too.Tacomacrew

I just had the car serviced and the light didin't go off. I never fill it up all the way. The gas cap isn't the orginial one I can tell.  When you open the gas door and try to put the gap in the slot to sit while your putting gas in, the cap is too small.  My other Jeep the cap fit right in there.

please just get your O2 sensors checked that will be your problem, it is someting to do with the exhaust system

If you have an Autozone near you, they may check it for free, at least they do near where I live.Tacomacrew

A MIL light will come on for many reasons. If your gas cap is not the correct one, I suspect the computer is sensing a leak in the EVAP system. This is common for not having the proper cap, leaving vehicle running while filling with gas and not tightening the cap. Also malfunctioning EVAP components. The best way to narrow it down is to have someone check it out with an OBDII scanner. It may not have anything to do with the cap, but at least you will know if it's a missfire, O2 sensor, Evap system and so on. Test it before replacing anything. If light starts to flash, have vehicle towed to shop for diagnostics and repair, as this is catalyst damaging signal. J. Velez ASE Certified Auto Tech.