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 below 0.06 V under enable conditions, ECM sets DTC P0137
( This DTC might be caused by the malfunction of Heater circuit, so, check the heater circuit first. )
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● Signal check, low | ● Poor connection ● Short to ground in signal circuit ● B1S2 ● ECM |
General Enable Conditions | ● After enough heated ● Battery voltage > 10.7V ● Catalyst temperature (model) < 800℃ | |
Case1 | Enable Conditions | ● Engine speed : 1000~3520 rpm ● Engine load : 20~56 % |
Threshold Value | ● B1S2 sensor voltage < 0.06 V | |
Diagnostic Time | ● 25 sec | |
Case2 | Enable Conditions | ● Sensor in cold condition |
Threshold Value | ● B1S2 sensor voltage < 0.06 V | |
Diagnostic Time | ● 0.1 sec | |
MIL | ● ON |
※ B1S1 : upstream oxygen sensor / B1S2 : downstream oxygen sensor
ITEM | Specification |
Heater Resistance(Ω) | Approx. 9.0Ω(20℃) |
