P0131: O2 Sensor Circuit Low Voltage (Bank 1, Sensor 1)
What this check-engine code means in plain English, what usually causes it, and what a fix typically costs.
What P0131 means
The upstream oxygen sensor (before the catalytic converter) on Bank 1 is reporting a voltage that is consistently too low. This sensor measures oxygen in the exhaust to help the engine computer adjust the air-fuel mixture. When the voltage stays low, the computer cannot properly control fuel delivery, which can affect performance and emissions.
What causes P0131?
Is P0131 safe to drive?
You can typically continue driving for a short period, but the engine may run poorly with reduced fuel economy and performance. Prolonged driving with a faulty O2 sensor can damage the catalytic converter over time, leading to much more expensive repairs.
P0131 repair cost
Industry-average estimates. Cost depends on whether it's just the sensor or if vacuum/exhaust leaks also need repair, and whether the sensor is accessible.
Which one is it for your car?
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