O2 Sensor Negative Voltage Bank 2 Sensor 1
The ECM detects a negative voltage on the signal line of oxygen sensor 1 on bank 2. This is unusual for narrow-band sensors and often indicates a short to a negative reference, ground offset, or a wide-band sensor wired incorrectly.
Affected components
- Oxygen sensor b2s1
- Wiring harness
- Ecm
Common causes
- High likelihood: Signal wire shorted to negative reference
- Medium likelihood: Ground offset between sensor and ECM
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.