power supply to O2 sensor
I was under the impression that it was powered by the fuel pump relay (if you open it you can see the 2 seperate relays).
The ovp supplys the power to the ecu meaning that even though the fuse on the ovp is blown the o2 sensor will still be getting power and sending a signal to the ecu, as will the air-flow meter and the coolant temp sensor. The ecu will not be able to adjust the mixture accordingly however as it is not powered up.
The Idle control solenoid and eha refer to a constant mixture setting.
That is my understanding.