O2 Sensor Pumping Current Trim Circuit Low Bank 1 Sensor 1
On a wide-band (broadband) O2 sensor, the trim resistor circuit that calibrates the pumping current is reading low on bank 1 sensor 1. Air-fuel feedback gain is wrong, causing rich or lean offsets.
Affected components
- Oxygen sensor wideband b1s1
- Sensor calibration resistor
- Wiring harness
Common causes
- High likelihood: Short in the calibration trim resistor
- Medium likelihood: Water intrusion in the sensor connector
- 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
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.