The codes are saying that there is a circuit fault. Could be damaged or corroded connectors, or not.
The circuit fault is detected by the PCM by means of an expected load or resistance in the circuit. The o2 heater circuit is provided power through the PCM, o2 sensor has a heater element inside to insure it is brought up to temperature quickly. The fuel management system can then work to control mixture. The sensor will eventually reach operating temp because it is in the exhaust stream, but just after start up, it doesn’t produce a signal and the fuel mixture is approximated by air and coolant temperature. They call this open loop, when the PCM is in control and has a signal from the o2, that is closed loop.
Back to the heater element, when just started, the o2 and the element are cold, the element’s resistance is lower, and current draw is higher, loading the circuit more. As the element gets hotter, it’s resistance increases, circuit load decreases, thus controlling the heater element.
The PCM monitors all this, when values aren’t as expected, those codes appear. Since it is “seeing” only values, and they are not what is expected. It can only call a circuit error. It doesn’t know what is causing the unexpected readings. There is a troubleshooting block diagram for testing this. It is manufacturer/ vehicle specific, and requires use of a volt meter and the wiring diagram along with the troubleshooting >if/then< procedure.
It could be as some as a blown fuse or bad relay. Then again, it could be a faulty PCM. Without the diagnostic procedure and diagram, you will not know where to look or what to condemn.
