What you have to determine, is it the sensor or is it the harness back to the ECM or the ECM itself?
About the only way to know for sure is with a scan tool.....with key on, attach a jumper wire to the harness end going to the ECM, not the sensor.....with nothing touching the end of the jumper, scan data for O2 sensor should be .455....now hold the end of the jumper with one hand and with the other hand touch the neg bat terminal....voltage should drop to zero....now touch the pos term and it should go to approx 1 volt....if you get this, the harness and ECM are ok, and you need a sensor.......