O2 Sensor Circuit Low Voltage (Bank 2, Sensor 1)
Same condition as P0131 but on bank 2. The upstream sensor sees a continuously lean exhaust on bank 2 or has a signal short to ground.
Affected components
- Oxygen sensor upstream
- Exhaust pipe pre cat
Common causes
- High likelihood: Exhaust leak upstream of the sensor
- Medium likelihood: Bank 2 running lean (vacuum leak, fuel pressure)
- Low likelihood: Connector pins corroded - high contact resistance
Possible symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- A drive cycle may be required after repair
Related codes
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.