Chery T21 2014 Service Manual page 411

Oxygen Sensor
Description
This vehicle is equipped with two oxygen sensors (upstream oxygen sensor and downstream oxygen sensor).
Oxygen sensors continually monitor the oxygen concentration in exhaust gas.
Operation
The oxygen sensor generates voltage depending on the oxygen content in exhaust gas. The sensor
generates low voltage when oxygen content is high, and high voltage when oxygen content is low. Therefore,
the sensor acts as a rich-lean switch.
The oxygen sensor is equipped with a heating element that keeps sensor at proper operating temperature
under all operating conditions.
Upstream Oxygen Sensor
The input signal from upstream heated oxygen sensor informs Engine Control Module (ECM) of the oxygen
content in exhaust gas. Based on this input signal, Engine Control Module (ECM) adjusts air-fuel ratio finely
by adjusting injector pulse width.
Downstream Oxygen Sensor
The downstream heated oxygen sensor signal is used to detect the catalytic converter deterioration. As
converter deteriorates, the signal from downstream oxygen sensor begins to match upstream oxygen sensor
signal except for a slight time delay. By comparing the signal from upstream heated oxygen sensor to the
signal from downstream oxygen sensor, Engine Control Module (ECM) calculates the efficiency of catalytic
converter.
Removal & Installation - Upstream Oxygen Sensor
(See page 09-13)
Removal & Installation - Downstream Oxygen Sensor
(See page 09-15)
Chery Automobile Co., Ltd.
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