Oxygen Sensor: Description and Operation

Oxygen Sensor:

Oxygen Sensor Operation:

^ The Heated Exhaust Gas Oxygen Sensor (HEGO), located in the right side exhaust pipe, detects the presence of oxygen in exhaust gas and produces a variable voltage signal monitored by the ECA.
^ It incorporates a platinum coated ceramic zirconia tube which generates voltage if there is a difference in oxygen concentration between the inside and outside of the tube.
^ A high concentration of oxygen (lean air/fuel ratio) produces a low voltage signal (below 0.4V). A low concentration of oxygen (rich air/fuel ratio) produces a high voltage signal (above 0.6V).
^ This feedback signal is used by the ECA to control air/fuel ratio during closed loop operation. Sensor voltage range is 0V to 1.1V.
^ To operate at peak efficiency, the oxygen sensor must heat up to approximately 300 - 400°C (572 - 752°F). To reach this temperature more quickly, the sensor is equipped with an ECA activated heating element.