DTC P0138: Notes
DTC P0138 DETECTION CONDITION AND POSSIBLE CAUSES
| DTC P0138 |
Rear HO2S circuit high input |
| DETECTION CONDITION |
- The PCM monitors the input voltage from the rear HO2S. If the input voltage from the rear HO2S sensor is above 1.2 V
for 0.8 s
, the PCM determines that the circuit input is high.
Diagnostic support note
- This is an intermittent monitor (HO2S).
- MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.
- PENDING CODE is available if the PCM detects the above malfunction condition during first drive cycle.
- FREEZE FRAME DATA is available.
- DTCs are stored in the PCM memory.
|
| POSSIBLE CAUSE |
- Rear HO2S malfunction
- Short to power supply in the wiring harness between rear HO2S terminal A and PCM terminal 1Y
- Rear HO2S or PCM terminal shorted
- PCM malfunction
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 Courtesy of MAZDA MOTORS CORP.
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