Oxygen (O2) Sensor

The oxygen sensor is mounted in the exhaust manifold where it is exposed to exhaust gases as they exit the combustion chamber. Sensor detects oxygen content of exhaust gas and produces a voltage signal proportional to that content for use by the ECU. Rich air fuel ratios will cause oxygen sensor to produce a high signal voltage (up to 1.0 volt), while lean air/fuel ratios will cause sensor to produce a low signal voltage (as low as .1 volt). The ECU receives these input signals and varies fuel injector duration (on time) to maintain proper air/fuel ratios during most operating modes.