HO2S(B1/S2) is in the rear side of Catalytic Converter to check the proper operation of catalyst. Oxygen density after the catalytic converter has to be within specific range (around 0.5V when there is no acceclation and deceleration.)
If the oxygen density changes in accordance with HO2S(B1/S1), it means the poor performance of catalytic converter.
If the sensor output is over 0.15 V under enable conditions, ECM sets DTC P0139.
( This DTC might be caused by the malfunction of Heater circuit, so, check the heater circuit first. )
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● Response rate | ● Poor connection ● leak or clog in intake air system ● Injector ● Fuel pressure ● B1S2 |
Enable Conditions | ● Time after fuel cut-off > 5 s ● Integrated air mass after fuel cut-off > 15 g ● Time after dew point end detected > 30 s | |
Threshold Value | ● B1S2 sensor voltage > 0.15 V | |
Diagnostic Time | ● 0.2 sec | |
MIL ON Condition | ● 2 driving cycle |
※ B1S1 : upstream oxygen sensor / B1S2 : downstream oxygen sensor
Specification | 0.1 ~ 0.9V |