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 there is not any signal activity, ECM sets DTC P0140.
( This DTC might be caused by the malfunction of Heater circuit, so, check the heater circuit first. )
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● No signal activity | ● Poor connection ● Open or short in signal circuit ● B1S2 ● ECM |
Enable Conditions | ● Time after dew point detected > 10sec | |
Threshold Value | ● Signal voltage changes higher than 2V after HO2S heater operation stops > 4 times | |
MIL | ● ON |
※ B1S1 : upstream oxygen sensor / B1S2 : downstream oxygen sensor
ITEM | Specification |
Heater Resistance(Ω) | Approx. 9.0Ω(20℃) |
