1998 Chevy Cavalier 1998 Cavalier communication problem

Electrical problem
1998 Chevy Cavalier 4 cyl Front Wheel Drive Manual

98 cavalier. In Oregon you have to take your car through DEQ for inspection. When I took my cavalier through to renew the tags, it won't talk to their OBD tool they plug in. So I can't pass. Yes the check engine light is on, and I have had problems with the wiring. The heater blower and radiator fan needed to be rewired. Do I need to just say screw it and get a new wiring harness? Or could this be a simpler problem that I can fix on my own. Need to get the car to talk to the OBD tool so I can get new tags. Other then the PCM not talking to the scan tool, the car runs fine. Checked all the fuses both on the side of the dash and under the hood, all good.