Oxygen (O2) Sensor (Lambda Signal)

Oxygen content of exhaust gases is detected by the oxygen sensor located in the exhaust manifold. This sensor converts the percentage of oxygen present in exhaust gases into an electrical signal which is transmitted to the MCU. MCU uses this information to determine air/fuel ratio and adjusts injection pulse width to obtain a 14.7:1 air/fuel ratio. When the O2 sensor is malfunctioning or disconnected, a constant .450 volt value is indicated to the MCU.