O2 sensors

I have been fighting an issue with random misfire codes and lean bank 1.
the random misfires are from p300, and or most all cylinders they jump around. When I scan it for live data it does not show voltage from 02 sensors or live short or long term fuel trim. It does show fuel trims in freeze frame after code trips. When I unplug the sensors it shows o2 heater circuit. The front sensors has been replaced and shows acceptable voltage when operating with a multimeter. The rear o2 sensor tests lean with multimeter. I am concerned that the computer is not getting the o2 data since my scanner shows no voltage.