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 (manifold) causes the longer switching time.
MALFUNCTION A
To judge the malfunctions of heated oxygen sensor 2, ECM monitors whether the voltage is unusually high during the various driving condition such as fuel-cut.
MALFUNCTION B
To judge the malfunctions of heated oxygen sensor 2, ECM monitors whether the minimum voltage of sensor is sufficiently low during the various driving condition such as fuel-cut.
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DTC No. |
CONSULT screen terms (Trouble diagnosis content) |
DTC detecting condition |
Possible cause |
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P0138 |
HO2S2 (B1) (O2 sensor circuit high voltage bank 1 sensor 2) |
A) |
An excessively high voltage from the sensor is sent to ECM. |
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B) |
The minimum voltage from the sensor is not reached to the specified voltage. |
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