The upstream oxygen sensor on bank 1 shows no useful signal. The engine may stay in open loop with higher consumption.
Causes vary by car. Test before you order a part.
Likely causes, most common first
- Faulty oxygen sensor
- Open circuit in the wiring
- Sensor heater fault
- Damaged connector
Parts usually involved
- Oxygen sensor Find at suppliers
- Sensor connector Find at suppliers
- Wiring harness Find at suppliers
Test before you replace
Test the signal, reference and heater circuits at the connector before fitting a new sensor.
General guidance for generic OBD2 codes. Always follow the maker's procedure for the car in front of you.