1998 GEO TRACKER User Comment / Complaint

Check engine light has been on since 9/30/02 when the pc module was replaced in my 1998 geo chevy tracker. i have taken it back to roger whitley chevrolet just about every other week from october to january 3, 2003. they have checked everything possible but cannot fix the problem. i was told not to worry it will not affect anything. if this is true then why do we need this system. i believe the problem might possibly be the pc module they installed is defective. the maintenance supervisor said that is not possible but yet he has checked the wiring and numerous other possibilities, but the light remains on.