P0131
Moderate Severity

P0131 — O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1)

System: Emissions

What P0131 means

Diagnostic Trouble Code (DTC) P0131 stands for O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1). This is a generic OBD2 diagnostic trouble code indicating that the engine computer (ECU) has registered an operational anomaly in the powertrain (p) systems.

When this error registers, the ECU records a freeze frame of sensor data and lights up the Check Engine Light on your dashboard to notify the operator of a system fault.

Symptoms of OBD2 Code P0131

When code P0131 is active, your car might exhibit the following common symptoms:

  • Check Engine Light on
  • Poor engine response and sluggish throttle
  • Increased fuel consumption

Common Causes of Code P0131

Faults that trigger this code typically include:

  • Cause 1: Faulty Bank 1 Sensor 1 Oxygen Sensor
  • Cause 2: Short to ground in the O2 sensor wiring harness
  • Cause 3: Exhaust leak upstream of the sensor
  • Cause 4: Very lean engine condition (e.g., fuel pump failure)

Can you drive with a P0131 code?

Yes, but the engine will run in open-loop mode, resulting in excessive fuel usage, black tailpipe smoke, and carbon buildup in the catalytic converter.

Expected Repair Cost Band

$100 - $250 for O2 sensor replacement.

Related Diagnostic Trouble Codes

If you have scanned multiple codes, see these related guides for troubleshooting context:

Frequently Asked Questions

What does Low Voltage mean for an O2 sensor?

It indicates either a failed sensor circuit or a mixture that contains an extreme excess of air (highly lean).