where is the oxygen sensor located

Oxygen sensors are located in the exhaust system. There are two types of oxygen sensors in terms of what they do. Upstream and Downstream. The upstream sensor is usually located in the exhaust manifold on a car such as a 1999 Buick Park Avenue and tests the amount of oxygen in the exhaust in order to adjust the fuel going into the engine. The downstream sensor is located in the exhaust pipe after the catalytic converter and measures the effectiveness of the catalytic converter. If you need anymore advice don't hesitate to call St. Joseph Automotive & Diesel at 217-469-2018.