The heated oxygen sensor is mounted or the front side of Catalytic Converter (warm-up catalytic converter) or in the front exhaust pipe, which detects the oxygen concentration in the exhaust gas. The heated oxygen snesor (HO2S) produces a voltage that varies between 0V and 1V. When the air/fuel ratio is lean, the oxygen concentration in the exhaust gas increases and the front HO2S outputs a low voltage (approximately 0 ~ 0.1 V).
When the air/fuel ratio is rich, the oxygen concentration in the exhaust gas decreases and the front HO2S output a high voltage (approximately 0.8 ~ 1 V). The ECM constantly monitors the HO2S and increases or decreases the fuel injection duration by using the HO2S signal, which is called closed-loop fuel control operation.
The ECM sets DTC P0132 if ECM detects signal voltage is higher than threshold.
Item
Detecting Condition
Possible Cause
DTC Strategy
Signal check, High
Contact resistance in connections.
Short to battery in signal circuit
Faulty HO2S(UP)
Faulty ECM
Enable Conditions
Dew point end detected
Target lambda = 1
Battery voltage > 10.7V
Exhaust gas temperature (model) : 600? ~ 800
No upstream O2 sensor error
Threshold Value
Signal output upstream O2 sensor > 1.08 V
Diagnostic Time
5 sec
MIL ON Condition
NO
?usvk : Sum of the signal voltage change value (HO2S (UP))
Temperature
Heater Resistance
0 ~ 1.0 V
9.0 ? (20?)
If you release the accelerator pedal suddenly after engine running about 4000 rpm, fuel supply will stop for short period and the O2 sensor service data in the Hi-Scan (Pro) will display values 200mV or lower. When you suddenly press on the accelerator pedal down, the voltage will reach 0.6 ~ 1.0 V.
When you let the engine idle again, the voltage will fluctuate between 200 mV or lower and 0.6 ~ 1.0 V. In this case, the O2sensor can be determined as good.