After driving on the highway, my downstream O2 sensor voltage was a steady 0.8V, which is high.

On the other hand, when idling before the drive, it was a steady 0.3V.

Is it normal for the downstream O2 sensor voltage to be so high after driving? Does this mean I have a bad catalytic converter, or is there another explanation?

  • How did you get on with the articles? See mechanics.stackexchange.com/q/82358/10976
    – Solar Mike
    Mar 31, 2021 at 8:30
  • @SolarMike Also, I read a few articles before asking, and they say that a high downstream (post-cat) O2 sensor voltage could mean that my catalytic converter is not working well. I’m just asking to get some second opinions
    – Asker
    Mar 31, 2021 at 13:11


You must log in to answer this question.

Browse other questions tagged .