Code result
P0131
O2 Sensor Circuit Low Voltage
Moderate severity
What it means
The upstream oxygen sensor signal is fixed at a low voltage, indicating the ECU sees a continuously lean exhaust on bank 1 — or the sensor signal path is shorted to ground.
Is it safe to drive?
Use caution
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical.
Most likely causes
Exhaust leak upstream of the sensor
highOne of the most commonly reported causes for this code — check this first.
Signal wire shorted to ground
mediumA plausible cause — test and verify before replacing parts.
Genuine lean running (vacuum leak, low fuel pressure)
mediumA plausible cause — test and verify before replacing parts.
Related help
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