Intake Air O2 Sensor Circuit Low Voltage Bank 1
Voltage on the intake air oxygen sensor signal line on bank 1 is below the expected window. A drifted or sluggish lambda sensor lets the mixture run lean or rich without correction — fuel economy and emissions suffer immediately.
Affected components
- Intake air o2 sensor b1
- Intake air o2 sensor heater b1
- Wiring harness
- Ecm
Common causes
- High likelihood: Signal wire shorted to ground
- Medium likelihood: Internal sensor short
- 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
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.