Diagnostics An oxygen sensor that’s going bad or has failed altogether won’t always throw a check engine light or trip a diagnostic trouble code. Sometimes if there’s an internal problem ...

In the present investigation, temperature sensitivity of the oxygen sensor was measured over a wide range of engine operating conditions. Sensor data were plotted in the form of contour lines of ...

I had a test done at local auto-parts store that showed a code of PO138. They told me this indicates a problem with the oxygen sensor. I replaced the oxygen sensor and the light never went out. I ...