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P0131: O2 Sensor Circuit Low Voltage (Bank 1, Sensor 1)
The front oxygen sensor on bank 1 is reading too low (lean).
Medium Severity
$150 – $500
Can I Keep Driving with Code P0131?
Yes, but expect poor fuel economy and possible damage to the catalytic converter over time.
What P0131 Means
The upstream O2 sensor on bank 1 is reporting a lean condition (too much oxygen in the exhaust). The cause could be the sensor itself, an exhaust leak, or a real lean condition from a vacuum leak or fuel delivery problem.
Common Causes
- Failed O2 sensor — see repair cost
- Exhaust leak ahead of the sensor
- Vacuum leak
- Weak fuel pump or clogged injector — see repair cost
Diagnostic Tips
- Check for exhaust leaks before replacing the sensor.
- If the lean condition is real, fix the underlying cause first.
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Does P0131 damage the catalytic converter?
Long-term yes. Running lean for thousands of miles can overheat and ruin the cat.