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Common codes
P0420P0300P0171P0455P0442P0128P0401P0113

P0131: Upstream O2 sensor circuit low voltage (Bank 1 Sensor 1)

Drive carefully. Get it checked within a week or two.

Can I drive with P0131?

Yes, but drive carefully and get it checked soon. The sensor reports a false lean condition, leading the computer to dump excess fuel.

What does P0131 mean?

P0131 stands for O2 Sensor Circuit Low Voltage (Bank 1, Sensor 1).

Symptoms you may notice

  • Drop in gas mileage by 10% to 15%
  • Slight hesitation or sluggish response when accelerating
  • Check engine light illuminated

How much does it cost to fix?

Repair costs for code P0131 depend on the specific underlying root cause, ranging from simple DIY checks to component replacement. The table below lists the most common causes and rough price ranges in USD:

  • Exhaust manifold leak drawing fresh air
    $60-$220 common
  • Defective Bank 1 Sensor 1 oxygen sensor
    $80-$210 common
  • Low fuel pressure or clogged fuel filter
    $70-$250 possible
  • Signal wire shorted to ground
    $45-$120 rare

What to do next

  1. Check for exhaust leaks before the catalytic converter.
  2. Inspect sensor wiring for contact with the hot exhaust pipe.
  3. Replace the Bank 1 upstream oxygen sensor.
Last updated: October 2026

Related codes

P0130 P0133 P0171 P0135
General guidance only, not a professional diagnosis. If the check-engine light is flashing, or the car is running rough, overheating or losing power, stop driving and get help.

About this code

Code P0131 means the sensor voltage stays below 0.1 volts for too long. If oxygen from an exhaust crack leaks into the sensor stream, the sensor signals lean even though combustion is normal. The computer responds by injecting excessive gasoline, which can ruin spark plugs and overheat the catalytic converter. Fixing it within a couple of weeks is recommended.