What does an oxygen sensor on an engine do?

Answer by  Amber40 (24961)

Well the oxygen or o2 sensor is basically a sensor that monitors the exhaust gases to determine whether the engine is receiving the correct amount of fuel. It gives feedback to the cars ecu to tell it to adjust the fuel mixture to reduce emissions and keep the engine efficient.

Answer by  BruceWayne (113)

The oxygen sensors before the catalytic converter mesures the amount of oxygen and unburnt fuel to monitor fuel trims and makes adjustments to the amount of fuel the engine gets. The oxygen sensors after the cat monitors the catalytic converters efficency of burning off the unspent fuel that passes through