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P0150: O2 Sensor Circuit Malfunction (Bank 2 Sensor 1)
Severity: Medium With a steady light and normal running, arrange diagnosis soon. Stop for a flashing light, severe misfire, overheating, or a glowing catalyst; do not assume those symptoms are only a sensor fault.
What does P0150 mean?
The upstream oxygen-sensor circuit on bank 2 is not working correctly. Bank 2 is opposite the bank containing cylinder 1; this input is used for mixture feedback on that bank.
Generic OBD-II definition: O2 Sensor Circuit Malfunction (Bank 2 Sensor 1). Confirm applicability in your vehicle service information.
Common causes
- Failed upstream sensor
- Corroded or loose bank 2 connector
- Wiring damaged by hot exhaust
- Exhaust leak introducing oxygen
Symptoms
- Rough idle or hesitation
- Poor fuel economy
- Check engine light
Diagnostic focus
If only bank 2 is affected, compare the two upstream signals and trims under the same conditions. A localized exhaust leak or connector issue can explain a one-bank fault.
Can I keep driving with P0150?
Severity: Medium With a steady light and normal running, arrange diagnosis soon. Stop for a flashing light, severe misfire, overheating, or a glowing catalyst; do not assume those symptoms are only a sensor fault.
If the check engine light is flashing or the car runs badly, stop driving and have it checked.
Typical fixes
- Identify the correct upstream bank 2 sensor
- Inspect its wiring and exhaust area
- Check signal response and fuel trims before replacing the sensor
Related codes
O2 Sensor Circuit Low Voltage (Bank 2 Sensor 1)P0152
O2 Sensor Circuit High Voltage (Bank 2 Sensor 1)P0153
O2 Sensor Circuit Slow Response (Bank 2 Sensor 1)P0154
O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 1)P0174
System Too Lean (Bank 2)
Sources & review
Definitions and diagnostic background checked 2026-11-06. Generic guidance, not a substitute for the service procedure for your exact year, engine, and transmission.