The Lambda sensoror oxygen sensor is located in the manifold or exhaust system. They analyse the amount of oxygen in the fuel being used by your car. The Lambda sensoris a vital component of any modern car, as it makes modern fuel injection possible and helps to regulate the emission of harmful gases into the atmosphere. This sensor then sends signals back to the ECU to calculate the engines fuelling requirements. There are quality Lambda sensors for every make and model of modern car and they are usually located in the exhaust stream. It is worth checking that your Lambda sensor is working properly, as faulty ones can lead to the catalytic converter becoming damaged and result in expensive repairs.