OBD-II code · Powertrain (generic)
P0131 O2 Sensor Circuit Low Voltage (Bank 1, Sensor 1)
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 with P0131?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyExhaust leak upstream of the sensor
- PossibleSignal wire shorted to ground
- PossibleGenuine lean running (vacuum leak, low fuel pressure)
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–3 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Oxygen Sensor Upstream, Exhaust Pipe Pre Cat
Related codes
- P0137O2 Sensor Circuit Low Voltage (Bank 1, Sensor 2)
- P0151O2 Sensor Circuit Low Voltage (Bank 2, Sensor 1)
- P012ETurbocharger/Supercharger Inlet Pressure Sensor A Circuit Intermittent/Erratic
- P012FEngine Coolant Temperature / Engine Oil Temperature Correlation
- P0130O2 Sensor Circuit Malfunction (Bank 1, Sensor 1)
- P0132O2 Sensor Circuit High Voltage (Bank 1, Sensor 1)
- P0133O2 Sensor Slow Response (Bank 1, Sensor 1)
- P0134O2 Sensor Circuit No Activity / Slow Response (Bank 1 Sensor 1)
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.