P0131 means o2 sensor circuit low voltage (bank 1, sensor 1). The upstream oxygen sensor on bank 1 is reporting abnormally low voltage — it's stuck reading 'lean.' The engine compute
Drive gently and get it diagnosed within days.
The upstream oxygen sensor on bank 1 is reporting abnormally low voltage — it's stuck reading 'lean.' The engine computer can't properly adjust the fuel mixture without it.
Sensors typically last 60k–100k miles.
Real lean condition the sensor is correctly reporting.
Dilutes exhaust with outside air.
Actually running lean.
Damaged sensor harness.
Typically $150–$400
O2 sensor replacement typically $150–$400. Estimates vary by vehicle. Costs are estimates and vary by vehicle, location, and shop.
Safe to drive short-term, but fuel economy suffers and the converter works harder. Fix within a week or two.
Typically $150–$400. O2 sensor replacement typically $150–$400. Estimates vary by vehicle.
Drive gently and get it diagnosed within days.
The most common cause is failed o2 sensor. Sensors typically last 60k–100k miles.