O2 Sensor Reference Voltage Circuit Range/Performance (Bank 1 Sensor 1)
The reference voltage that the ECU supplies to the wide-band oxygen sensor on bank 1, sensor 1 drifts outside the expected range. The reference is the baseline against which the cell voltages are measured; a drift falsifies every lambda calculation.
Affected components
- Oxygen sensor upstream
- Oxygen sensor wiring
- Ecm
Common causes
- High likelihood: Reference circuit drift in ECU
- Medium likelihood: High resistance in reference wiring
- Low likelihood: Sensor element aged beyond calibration window
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.