heater circuit codes

i have a 95 ranger 2.3 5 spd with 290k that is obd2 certified. i have po135 and a po141 codes for the o2 sensor heater circuit i have replaced the o2 sensors and tested the new ones. they tested fine. i have also tested the wiring to the pcm that was also fine and i bought a used computer out of a running ranger with no codes and all the readiness monitors ok and the light keeps coming back on.i have to pass emissions and i dont know what else to do or try any help would be greatly appreciated