What Does An O2 Sensor Do? What Every Mechanic Should Know
Mechanics understand that engine parts have become complicated with sensors and computers running the show. The O2 sensor is one of those parts that still causes trouble for mechanics, and some wonder what does an O2 sensor do?
The O2 sensor is an integral part of any engine manufactured after 1980 when engine controls became electric. The O2 sensor monitors oxygen levels in the emissions and sends constant updates to the vehicle’s main computer.
Most vehicles have more than one O2 sensor. If one of them does not work correctly, the central computer will turn on the check engine light. The O2 sensors are continually monitoring and altering the emissions based on several factors.
New vehicles have at least two sensors. One is close to the engine, on the exhaust pipe at the beginning of the emissions system. The second is closer to the end of the emissions system near the muffler and catalytic converter.
As O2 sensors are in their fourth decade of existence, they have longer lifespans than the earlier versions. Older models lasted 60,000 miles, but new ones will run for 100,000 miles or more.
When an O2 Sensor Begins to Fail?
It is difficult to tell if an O2 sensor is going bad unless you have a diagnostic code reader. However, there are a few clues that could suggest the sensors is failing. One is that your vehicle’s gas mileage decreases without any other explanation. Performance tends to drop off, too.
Oxygen sensors fail as they age, but other reasons cause them to stop working correctly. If you put contaminated fuel in your car, the O2 sensors could fail sooner than expected.