Oxygen (O2) Sensor

The O2 sensor detects oxygen content in the exhaust gas and sends this information to the ECU/ECM. In operation, the ECU/ECM receives signals from the O2 sensor and varies the duration during which fuel is injected. A high voltage signal indicates a rich mixture. A low voltage signal indicates a lean mixture.

The O2 sensor is heated electrically for rapid warm-up and constant operating temperature. Power to the heating element is supplied whenever ignition switch is turned to ON position.