O2 Sensor Circuit Low Voltage (Bank 2 Sensor 2)
The ECU detects abnormally low voltage from the downstream O2 sensor on bank 2 (alternate definition mapping in some manufacturers' interpretation). Indicates persistent lean reading, open sensor or wiring shorted to ground.
Affected components
- Oxygen sensor b2s2
- Oxygen sensor wiring
Common causes
- High likelihood: Lean condition on bank 2
- Medium likelihood: O2 sensor failed
- 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.