Which code? "EVAP" is not a code definition. It could be a lot of stuff. Find out exactly which code.
All TJs are OBDII-equipped and the code will read off as "Pxxxx" with the X's being a four digit number. My EVAP code was P1494, which means "Leak Detection Pump (LDP) pressure switch problem - electrical or the pump itself." Knowing the exact code and what it indicates will save you a lot of time in your search.
are all of the OBDII codes the CEL can warn you about, including the EVAP ones.