ECM checks output signals from HO2S under detecting condition. ECM/PCM judges it's signals too slow and sets P0139, if output signal from rear HO2S isn't increased up to specification level within a short time after fuel cut.
(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, high | 1. Poor connection 2. HO2S(S2) 3. leak or clog in intake air system 4. ECM/PCM |
Enable Conditions |
•
Dew point end detected
•
Fuel feed back control active
•
Exhaust Gas temperature is higher than 350℃ and lower than 800℃
•
No upstream O2 sensor heater error
•
Fuel Cut-off condition
•
Integrated air mass during fuel cut-off > 0.62kg ~ 0.78kg
•
Rear O2 sensor monitoring - completed
•
Rear O2 sensor heater monitoring - completed
•
No misfire
•
No fuel system error, No PCV error
•
No CKP sensor error, No CMP sensor error | |
Threshold Value |
•
S2 signal is higher than 0.15V | |
Diagnostic Time |
•
2 sec. | |
Mil On Condition |
•
3 driving cycles |
※ S1 : upstream oxygen sensor / S2 : downstream oxygen sensor
