DTC P0140: Notes
DTC P0140 DETECTION CONDITION AND POSSIBLE CAUSES
| DTC P0140 |
Rear HO2S no activity detected |
| DETECTION CONDITION |
- The PCM monitors the input voltage from the rear HO2S when the following conditions are met. Under the following monitoring conditions, if the input voltage from the rear HO2S does not even exceed 0.55 V
though the short term fuel trim is controlled up to 20.5%
for 9.6 s
, the PCM determines that sensor circuit is not activated.
MONITORING CONDITIONS
- HO2S, HO2S heater and TWC repair verification drive mode
- The following conditions are met for above 20.8 s
- Engine speed is above 1, 00 RPM
- Engine coolant temperature is above 70°C {158°F}
- Rear HO2S voltage is above 0.1 V
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.
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| POSSIBLE CAUSE |
- Rear HO2S deterioration
- Rear HO2S heater malfunction
- Exhaust system leakage
- Open circuit or short to ground in the wiring harness between rear HO2S terminal A and PCM terminal 1Y
- Insufficient compression
- Engine malfunction
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 Courtesy of MAZDA MOTORS CORP.
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