I have no reading from my both upstream O2 (neither via scanner nor when I back probe them), but both O2 work fine when I do bench test by heating them with the torch: the voltage raises as I heat the sensor and drops as I remove the torch (as expected). I checked the heating circuit - continuity is...

I have my XC90 2007 with 213k miles. I bought the car new. No issues. Never changed the transmission oil.

Hi all, I am having problem to detect the voltage change from "lean" to "reach" on my both upstream O2 sensors. Here are the tests I performed: 1) I back probed signal and ground wires while sensor is in the car and connected to the harness, but no reading on the millimeter. 2) W...