Cars made in 1996 and after are required to have a second oxygen sensor that is located below the catalytic converter. This O2 sensor monitors the operating efficiency of the catalytic converter.

Why Replace A Faulty Oxygen Sensor? A faulty sensor cannot transmit accurate data to the car's computer, causing the engine to run unbalanced. An unbalanced engine either burns fuel with too much or ...

This month, we’re moving downstream to diagnose a bad O2 sensor. The oxygen sensor is a heat-activated sensor downstream in the exhaust system that monitors the air/fuel ratio via a chemical ...