Powertrain
generic / SAE
P0137
O2 Sensor Circuit Low Voltage (Bank 1, Sensor 2)
The downstream oxygen sensor signal is fixed at a low voltage. Either the catalyst is letting unburned oxygen through (sensor sees lean), the sensor itself is shorted to ground, or the catalyst is so degraded that the downstream signal mirrors a lean upstream condition.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number1 / 37
Possible causes
- Signal wire shorted to ground medium
- Catalyst degraded (often appears before P0420) medium
- Exhaust leak between catalyst and downstream sensor low
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
Inspection / repair
- Difficulty: medium
- DIY: possible
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References
sae:J2012