try this before spending any cash.
unplug the battery for about an hour. then on a sunday morning (least amount of traffic ) starting with a cold car do a drive cycle. sometimes you have to do this a few times for it to complete. remember the car has to be cold every time you do a drive cycle
OBD II Drive Cycle (reset car diagnostic monitors )
if thisn doesnt work its time for a shop with star das to look at it.
are you in tn? what part?