DTC Detection Logic
The heated oxygen sensor 2 has a much longer switching time between rich and lean than the air fuel ratio (A/F) sensor 1. The oxygen storage capacity of the three way catalyst 1 causes the longer switching time. To judge the malfunctions of heated oxygen sensor 2, ECM monitors whether the switching response of the sensor's voltage is faster than specified during various driving conditions such as fuel cut.
| DTC No. | CONSULT screen terms (Trouble diagnosis content) | DTC detecting condition | Possible cause |
|---|---|---|---|
| P0139 | HO2S2 (B1) (O2 sensor circuit slow response bank 1 sensor 2) |
The switching time between rich and lean of a heated oxygen sensor 2 signal delays more than the specified time computed by ECM. |
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