OBD-II code guide
P0137 Oxygen Sensor Circuit Low Voltage Bank 1 Sensor 2
P0137 means the downstream oxygen sensor voltage on bank 1 is lower than expected.
What it means
The post-catalyst sensor signal may show excess oxygen, wiring issues, or sensor failure.
Common symptoms
- Check engine light
- Usually normal driving
- Emissions failure
- Possible exhaust leak noise
- Fuel economy may change
Likely causes
- Exhaust leak
- Downstream oxygen sensor fault
- Wiring issue
- Lean running condition
- Connector contamination
First checks
- Inspect exhaust after the converter.
- Check downstream sensor wiring.
- Look for lean codes.
- Review sensor voltage before replacing parts.