Q: In my vehicle, the check engine light comes on and then goes off and it is now back on. I had a test done at local auto-parts store that showed a code of PO138. They told me this indicates a ...

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 ...

Zak is new to the CarBuzz team, working as a freelance content writer. When Zak isn't writing How To articles for CarBuzz he's working as a high school automotive technology instructor. Before ...

Modern vehicles are pretty complicated pieces of tech. Apart from emissions and other vital functions, the engine control system relies heavily on several sensors to regulate performance. That is ...