DTC P0137: Notes
DTC P0137 DETECTION & CONDITION POSSIBLE CAUSES
| DTC P0137 |
Rear HO2S circuit low input |
| DETECTION CONDITION |
- The PCM monitors input voltage from rear HO2S. If the input voltage from the rear HO2S is below 0.1 V
for 35.2 s
the PCM determines that circuit input is low.
MONITORING CONDITIONS
- HO2S, HO2S heater and TWC repair verification drive mode
- Following conditions are met.
- Engine speed is above 1,500 rpm.
- Engine coolant temperature is above 70 °C {158 °F}
.
- Fuel injector control in rear HO2S closed loop control.
- 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 0.1 V
though the short term fuel trim is controlled, the PCM determines that sensor circuit input is low.
MONITORING CONDITIONS
- HO2S, HO2S heater and TWC repair verification drive mode
- Following conditions are met for above 20.8 s
.
- Engine speed is above 1,500 rpm.
- Engine coolant temperature is above 70 °C {158 °F}
.
Diagnostic support note
- This is a continuous monitor (HO2S).
- MIL illuminates if PCM detects the above malfunctioning 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 PCM detects the above malfunction conditions during first drive cycle.
- FREEZE FRAME DATA is available.
- DTC is stored in the PCM memory.
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| POSSIBLE CAUSE |
- Rear HO2S malfunction
- Connector or terminal malfunction
- Short to ground in wiring between rear HO2S terminal A and PCM terminal 2Q
- Open circuit in wiring between rear HO2S terminal A and PCM terminal 2Q
- Open circuit in wiring between rear HO2S terminal B and PCM terminal 1U
- PCM malfunction
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 Courtesy of MAZDA MOTORS CORP.
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