O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)
The ECU detects that the downstream oxygen sensor on bank 1 reports an abnormally high voltage signal, suggesting a persistently rich exhaust condition past the catalyst, a shorted sensor, or wiring shorted to a voltage source.
Affected components
- Oxygen sensor b1s2
- Oxygen sensor wiring
- Catalytic converter bank1
Common causes
- High likelihood: Engine running rich (leaking injector, high fuel pressure)
- Medium likelihood: Sensor signal wire shorted to voltage
- Medium likelihood: Downstream O2 sensor failed
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.