The oxygen sensor is an emissions-control device. Since the invention of modern technology, government regulation and the "Clean Air Act," the mission to reduce vehicle pollution is at the forefront of global politics.
A sensor is an electrically controlled device designed to monitor conditions. As information is received, the sensor sends information back to the computer.
The O2 sensor monitors emissions. Signals are sent to the computer to maintain proper air/fuel mixture.
The sensor is located in the exhaust system before the converter.
Sensor 2 is located in the exhaust system on or after the converter.
Oxygen sensors receive input from the spent exhaust gases exiting from the vehicle's combustion chambers. Once values are compared, the sensors will output the information to the computer, and if the values are not within specifications, the computer will illuminate the "check engine light," alerting the driver of a potential problem.