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.
P0138 HO2S2 - DTC DESCRIPTION
| DTC | M.U.T.-III SE screen terms (Trouble diagnosis content) | DTC detection condition | |||
|---|---|---|---|---|---|
| P0138 | 00 | O2 sensor bank 1 sensor2 (B1) (O2 sensor circuit high voltage bank 1 sensor 2) |
A | Diagnosis condition | - |
| Signal (terminal) | Heated oxygen sensor 2 signal | ||||
| Threshold | An excessively high voltage from the sensor is sent to ECM |
||||
| Diagnosis delay time | - | ||||
| B | Diagnosis condition | - | |||
| Signal (terminal) | Heated oxygen sensor 2 signal | ||||
| Threshold | The minimum voltage from the sensor is not reached to the specified voltage | ||||
| Diagnosis delay time | - | ||||