If my memory serves right, these models had leak detection pumps, they failed often. Also the evap purge solenoid sticks open on almost all of these Chrysler products. I have replaced hundreds of them. So many, sometime my parts guy was back order on them :ROFL
I agree with kev2, a scanner is a must here, so you can activate purge solenoid, do a LDP test etc. But these are sophisticated scanner's and not easily bought on a tight budget.
If you have a couple grand in the bank you can get one, I highly suggest a respected shop. Cuz just a code say's nothing, Need a smoke machine and skill's and DVM, and know how to interpret graphing etc. And if you need emission testing in your state/province, not a easy job for the backyard mechanic.