I own a '99 4x4x4. It keeps giving me this code: P1153 - HO2S Insufficient Switching Bank 2 Sensor 1

I put in a new sensor to no avail. I tried the procedure listed here. Regardless of what I do the scan tool always reads just under 0.5V. According to the procedure it is a wiring issue. I checked all the wires and they are good.

Chasing other routes I fixed a vacuum leak and replaced the plug wires (plugs, distributor cap and rotor are all new it was the only thing I hadn't replaced.)

I'm at a loss for what to try next. Does any one here know what could be causing this or even just more detail on how the system works? I fear it is an issue with a circuit in the PCM, but I'm not sure how to test that.

 

I have seen in other threads mention of the brand of O2 sensor making a difference. Is there any merit to this? If so should I go get an ACDelco one or head to the dealer and get whatever they carry?