Every new BMW, and all BMW cars made from 1980 on, have an oxygen sensor, often called an "O2 sensor". The oxygen sensor is part of your BMW's emissions control system and feeds data to BMW engine management computer. The oxygen sensor is positioned in the exhaust pipe and can detect rich and lean mixtures. The goal of the oxygen sensor is to help the engine run as efficiently as possible and also to produce as few emissions as possible. When your BMW oxygen sensor fails, the computer can no longer sense the air/fuel ratio, so it ends up guessing -- resulting in poor performance, poor gas mileage, and increased pollution. Make sure your BMW engine performs as it should, and doesn't use more fuel than it needs to by simply changing your oxygen sensor today. We carry Bosch oxygen sensors, and in some cases Genuine BMW oxygen sensors or OEM oxygen sensors.