P0151: Upstream O2 sensor low voltage (Bank 2 Sensor 1)
Drive carefully. Get it checked within a week or two.
Can I drive with P0151?
Yes, but drive carefully and get it checked soon. Bank 2 sensor falsely reads lean; computer dumps excess fuel into Bank 2.
What does P0151 mean?
P0151 stands for O2 Sensor Circuit Low Voltage (Bank 2, Sensor 1).
Symptoms you may notice
- Drop in gas mileage by 10% to 15%
- Slight hesitation or sluggish response when accelerating
- Check engine light illuminated
How much does it cost to fix?
Repair costs for code P0151 depend on the specific underlying root cause, ranging from simple DIY checks to component replacement. The table below lists the most common causes and rough price ranges in USD:
- Exhaust leak before Bank 2 sensor
- Defective Bank 2 upstream O2 sensor
- Signal wire shorted to ground
- Bank 2 fuel injector restriction
What to do next
- Check for exhaust leaks at Bank 2 manifold flange.
- Inspect wiring insulation on Bank 2 sensor.
- Replace the upstream Bank 2 oxygen sensor.
Last updated: October 2026
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General guidance only, not a professional diagnosis. If the check-engine light is flashing, or the car is running rough, overheating or losing power, stop driving and get help.
About this code
Code P0151 indicates Bank 2 Sensor 1 is locked below 0.1V. Safe to drive for short distances.