Oxygen Sensor Replacement
What is an oxygen sensor?
The oxygen sensor, sometimes called an O2 sensor, is a device mounted in the exhaust system that constantly monitors the oxygen content in the gases that exit the engine.
Oxygen sensors are located before and after the catalytic converter. A vehicle may have two to five oxygen sensors, and sometimes even more.
How does the oxygen sensor work?
The information from the oxygen sensor is used by the engine's computer to help determine how much fuel is needed so that the engine will run efficiently. The sensor sends this information by producing voltage when the sensor is heated. The voltage rises and falls as oxygen levels in the exhaust rise and fall.
A failed oxygen sensor may cause the vehicle to fail an emissions test. The failed sensor will cause a trouble code to be set and the Check Engine Light to illuminate.
Oxygen sensors can fail if they are contaminated with oil, coolant, or silicone. If fluid contamination has caused an oxygen sensor failure, the source of the fluid must be resolved or the new sensor may be ruined.