Got a drivability problem? It could be your oxygen sensor! Poor mileage? Rough running engine? Failed inspection? If your vehicle was manufactured in the last three decades, chances are it uses one or more Oxygen (O2) Sensors to help keep the engine running smoothly and help control excess exhaust emissions. The oxygen sensor is a key part of today's sophisticated car and light truck engine. Yet it's also one of the most commonly overlooked causes of many of today's drivability problems. An oxygen sensor that's not functioning or not working properly can cause more than just higher emissions levels in your vehicle. It can cost you money: it can have you going back for tune-up after tune-up. it can seriously damage your vehicle's catalytic converter. it can cost you up to 6 extra fill-ups a year, 70 gallons of gas or more, in reduced mileage alone. How an oxygen sensor works in your engine. An oxygen sensor is used by your vehicle's on-board computer to measure and report the amount of oxygen passing through the exhaust system when the vehicle is running. It continually monitors the exhaust, looking for a precise mixture of 14.7 parts of air to 1 part of fuel. This is the ideal air/fuel mixture ratio for today's gasoline engine. Whenever the oxygen sensor detects an air/fuel mixture higher or lower than 14.7 to 1, it immediately tells the computer to either add or reduce the amount of fuel being sent to the engine until the correct mixture is achieved. This "sense-signal-correct" process can happen many times a second on the average vehicle. What happens when your oxygen sensor needs to be replaced? The heart of today's oxygen sensor is a special ceramic element that actually extends into your exhaust pipe. Its unique composition and construction allow it to simultaneously sample the oxygen in your exhaust and the oxygen in the air outside, and continually compare them. Oxygen sensors operate in your exhaust system at temperatures above 600°F. The sensor can be damaged or ruined if your engine runs rich (too much fuel) for a long period of time, if you use leaded gasoline even briefly, or if any of a number of engine malfunctions cause a build-up of carbon on the ceramic element. The part of the sensor outside the exhaust pipe is sensitive, too. If undercoating, antifreeze, engine oil or some silicone gasket sealers come into contact with it, they damage the sensor's ability to report to the computer, leaving the sensor useless. Why your service professional may suggest a new BWD brand oxygen sensor. If testing by your service professional indicates that you need a new oxygen sensor, chances are, he'll recommend you replace it with a new BWD brand oxygen sensor. Back to Things You Should Know Visit our Resource Library for available downloads