DTC P0138: Notes
DTC P0138 DETECTION & CONDITION POSSIBLE CAUSES
| DTC P0138 |
Rear HO2S circuit high voltage |
| DETECTION CONDITION |
- The PCM monitors the input voltage from the rear HO2S when the engine is running. If the input voltage is more than 1.2 V
, the PCM determines that the rear HO2S circuit voltage is high.
Diagnostic support note
- This is an intermittent monitor (HO2S).
- The 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 the first drive cycle.
- FREEZE FRAME DATA is available.
- The DTC is stored in the PCM memory.
|
| POSSIBLE CAUSE |
- Rear HO2S malfunction
- Connector or terminal malfunction
- Short to power supply in wiring harness between rear HO2S terminal A and PCM terminal 2Q
- PCM malfunction
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 Courtesy of MAZDA MOTORS CORP.
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