FRONT HEATED OXYGEN SENSOR (HO2S) CONSTRUCTION/OPERATION [ZY]

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• Installed to the exhaust manifold (front of the WU-TWC).

• The wide-range air/fuel ratio sensor is a pump cell type sensor, using both the oxygen concentration cell action and oxygen pump cell action, and can detect the oxygen concentration (air/fuel ratio of the air-fuel mixture) in the exhaust gas in all ranges, from lean to rich.

• A heater is built into the sensor to facilitate the activation of the HO2S at engine startup (when the exhaust gas temperature is low).

Operation

• The wide-range air/fuel ratio sensor converts the oxygen concentration in the exhaust gas into a current value, and sends the value to the PCM.

• The PCM calculates the l (lambda) value of the air-fuel mixture based on the received current value.

• (l (lambda)) = (actual air/fuel ratio)/(stoichiometric air/fuel ratio)