Aging of Oxygen Sensor After Catalytic Converter (Cylinders 1 - 3)

P0139

Aging of Oxygen Sensor After Catalytic Converter (Cylinders 1 - 3)

Function
The oxygen sensors after the catalytic converter serve the purpose of pilot control of the oxygen sensors ahead of the catalytic converter. This allows correction of any shift in the oxygen sensor characteristic ahead of the catalytic converter.

Diagnosis conditions
- Engine speed between 720 rpm and 2400 rpm.
- Engine load between 0.8 ms and 2.6 ms.
- Oxygen sensor heating active.
- Oxygen sensing before catalytic converter active.
- Calculated catalytic converter temperature [>] 352 °C.
- No secondary air injection.
- No fuel tank ventilation.
- No faults in fuel tank ventilation or secondary air injection.

P0139-P0159:

Wiring Diagram







Diagnosis Procedure







1 Road test vehicle or perform short test.

1. Erase fault memory.
2. Heat oxygen sensors (road test vehicle under load, run engine at high rpm with no load).
3. Road test vehicle or perform short test, ensuring that the diagnosis conditions are reached.
4. Read fault memory.