We tested popular wideband O₂ controllers against lab-grade equipment to see how accurate their lambda readings really are under real engine conditions.

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 ...

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 ...

Modern cars rely on a dense web of sensors to manage everything from fuel delivery to collision avoidance, and when one fails, the result can range from a minor annoyance to a four-figure repair. I ...

As the name suggests, oxygen sensors in a car’s exhaust system sniff for oxygen, the presence of which indicates incomplete combustion and unchecked pollution. This can trigger the check engine light.

Q: Where are the oxygens sensor(s) located on a 1999 Toyota Corolla? A: In the exhaust system, before and after the catalytic converter. Q: We just recently purchased a 1996 Ford Explorer, and it has ...