O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1)
The front lambda sensor, ahead of the catalyst, measures the oxygen left in the exhaust. With it the ECU corrects the air–fuel mixture several times a second.
What the car has detected
The front sensor voltage stays too low: it is usually the wiring or the sensor itself.
It is not dangerous, but the car may use more fuel and fail the inspection. Have it checked when you can.
Symptoms
- Engine warning light on
- Higher fuel use
Possible causes
- Broken or shorted wire, or a loose or corroded connector
- Worn or faulty oxygen sensor
- Exhaust leak ahead of the sensor
Checks for the garage
- Check the sensor wiring and connector
- Compare the live data reading with the expected one
- Look for exhaust leaks
Next step
Ask for the lambda sensor wiring and the sensor to be checked before it is replaced, and for exhaust leaks to be looked for.
You can keep using the car and book a visit without hurry.