DTC P0031: Notes
DTC P0031 DETECTION CONDITION AND POSSIBLE CAUSES
| DTC P0031 |
Front HO2S heater circuit low input |
| DETECTION CONDITION |
- The PCM monitors the front HO2S heater output voltage. If the PCM turns the front HO2S heater off or on but the front HO2S heater circuit voltage remains low the PCM determines that the front HO2S heater circuit has a malfunction.
NOTE:
- The front HO2S heater is controlled by a duty signal.
Diagnostic support note
- This is a continuous monitor (HO2S heater).
- 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.
- DTCs are stored in the PCM memory.
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| POSSIBLE CAUSE |
- Front HO2S heater malfunction
- Connector or terminal malfunction
- Open circuit in the wiring harness between main relay and front HO2S terminal 2B
- Short to ground in the wiring harness between main relay and front HO2S terminal 2B
- Open circuit in the wiring harness between front HO2S terminal 2D and PCM terminal 4AD
- Short to ground in the wiring harness between front HO2S terminal 2D and PCM terminal 4AD
- PCM malfunction
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 Courtesy of MAZDA MOTORS CORP.
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