If abnormal response rate of downstream O2 sensor under enable condition is detected, ECM sets DTC P0139.
Item | Detecting Condition | Possible Cause |
DTC Strategy |
•
Rationality check | 1. Poor connector connection 2. Air leak in intake or exhaust system 3. Faulty fuel system 4. Faulty upstream O2 sensor 5. Faulty ECM/PCM |
General Enable Condition |
•
30 sec. elapsed after downstream dew point end detected
•
Battery voltage is higher than 11V
•
Exhaust gas temperature around O2 sensor is higher than 350℃(662℉)
•
No downstream O2 sensor heater error | |
Enable Condition |
•
Integrated air mass during fuel cut-off is 0.25 kg
•
Engine speed is at between 1250 RPM and 3520 RPM
•
Exhaust gas mass flow is higher than 10 kg/h
•
Deviation of exhaust gas mass flow is at between -150 kg/h and 150 kg/h
•
Fuel cut-off condition
•
Downstream O2 sensor voltage before fuel cut is at between 0.625V and 0.85V
•
Exhaust gas temperature around O2 sensor is higher than 425℃(797℉) | |
Threshold Value |
•
Transition time(Minimum duration of downstream O2 sensor voltage from 0.60 to 0.25V during fuel cut off) is higher than 0.30 sec. (Average value of 3 samples) | |
Diagnostic Time |
•
30 sec. | |
MIL ON Condition |
•
3 driving cycles |
