HEATED OXYGEN SENSOR (HO2S) [SKYACTIV-G 1.5, SKYACTIV-G 2.0]
id0140g8004700
Purpose
• Detects the oxygen concentration (air/fuel ratio) in the exhaust gas as basic information for mainly determining the fuel injection amount and as information for determining the deterioration of the catalytic converter.
Function
• Detects the oxygen concentration (air/fuel ratio) in the exhaust gas and sends it to the PCM as an oxygen concentration (air/fuel ratio) signal.
HO2S characteristic
• The HO2S detects rich/lean of the oxygen concentration compared to the theoretical air/fuel ratio.
Construction
• The HO2S is located on the pipe between the warm-up three-way catalyst (WU-TWC) and the three-way catalyst (TWC) of the catalytic converter.
• A zirconia element has been adopted for the detection area of the HO2S.
• A zirconia element generates voltage according to the difference in the oxygen concentration between atmosphere side and exhaust gas side.
• The zirconia element is kept at a specified temperature by the heater for quick activation.
Operation
• Sends signals, which vary according to the oxygen concentration (air/fuel ratio), to the PCM.
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― When the oxygen concentration in the exhaust gas is high, the output voltage is low because there are almost no difference in the oxygen concentration. (Output voltage approx. 0—0.5 V)
― When the oxygen concentration in the exhaust gas is low, the output voltage is high because the difference in the oxygen concentration is large. (Output voltage approx. 0.5—1.0 V)
• The PCM applies approx.
1.5 V to the voltage output from the HO2S to prevent false diagnosis of the HO2S output voltage.
Fail-safe
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DTC No.
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Fail-safe function
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P0037:00
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• Stops fuel feedback control.
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P0038:00
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• Stops fuel feedback control.
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P0137:00
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• Fixes the output duty value of the A/F sensor heater control.
• Stops fuel feedback control of A/F sensor.
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