P0131Severity: Medium
P0131 – Oxygen Sensor Low Voltage (Bank 1 Sensor 1)
The upstream O2 sensor shows persistently low voltage (lean).
What it means
The pre-catalyst oxygen sensor outputs low voltage indicating a lean mixture. Real lean, an exhaust leak or a sensor fault can be responsible.
Symptoms
- Check-engine light
- Increased fuel use
- Rough idle
Common causes
- Exhaust leak
- Genuinely lean mixture (vacuum/MAF)
- Faulty O2 sensor
- Wiring issue
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Frequently asked questions
What does trouble code P0131 mean?
P0131 – Oxygen Sensor Low Voltage (Bank 1 Sensor 1). The pre-catalyst oxygen sensor outputs low voltage indicating a lean mixture. Real lean, an exhaust leak or a sensor fault can be responsible.
Can I drive with a P0131 code?
You can usually drive short distances, but it's best to have it checked before it gets worse.