o2 sensor help

[GTDrifter]

My girls outback had a bad o2 sensor. It was replaced and threw a code for high voltage on that sensor. Hers has 4 wires, black gray and two white. I swapped the two white wires and its still throwing a code. Any idea?

[Odycee]

4 wires= 12v grey, ground black, heater wires are white. So swapped 2 white wires you didn't change anything. My guess your code is P0141.

[GTDrifter]

4 wires= 12v grey, ground black, heater wires are white. So swapped 2 white wires you didn't change anything. My guess your code is P0141.
I forget the what the code was. It said it was for high voltage bank 1 sensor 2.

[Odycee]

4 wires= 12v grey, ground black, heater wires are white. So swapped 2 white wires you didn't change anything. My guess your code is P0141.
I forget the what the code was. It said it was for high voltage bank 1 sensor 2.

P0138 02 Sensor Circuit High Voltage (Bank I Sensor 2)

Rear O2 sensor is meant to monitor excessive/lack of O2 to feedback to ECM to control A/F ratio(front O2.) It supposed to operate between 0 to 1V (ideally 0.45mV) and flat constant line, your O2 operated out of range, probably larger than 1V at certain peaks so the ECM reported high voltage out of range. If you have a ELM ($15-20) with Torque app($5), you can see it on your bluetooth phone or tablet. Did you replace with a OEM Denso sensor or a GENERIC one? I suspect you replace with a generic O2 sensor.

It's important to stay with OEM because the ECM expect a certain load resistance value from the sensor with 12V input. An too large or too small resistance value will operate at different range, in your case it's in the upper range therefore larger resistor load than the OEM one.