O2 Sensor Pumping Current Circuit Low (Bank 1 Sensor 1)
Pumping current at the bank 1 sensor 1 wide-band lambda probe is below the lower limit — short to ground or sensor at end of life.
Affected components
- Oxygen sensor wideband
- Oxygen sensor wiring
Common causes
- High likelihood: Pump line shorted to ground
- Medium likelihood: Wide-band sensor aged
- 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.