P0137: Downstream O2 sensor circuit low voltage (Bank 1 Sensor 2)
You can keep driving. Get it checked when convenient.
Can I drive with P0137?
Yes, you can keep driving. Downstream monitoring circuit issue; does not harm engine operation.
What does P0137 mean?
P0137 stands for O2 Sensor Circuit Low Voltage (Bank 1, Sensor 2).
Symptoms you may notice
- Check engine light on with no noticeable change in how the car drives
- Vehicle fails state emissions smog test
- Normal engine power and shifting
How much does it cost to fix?
Repair costs for code P0137 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:
- Defective downstream oxygen sensor
- Exhaust pipe leak near downstream bung
- Undercarriage wiring shorted to ground
- Water inside the electrical plug
What to do next
- Check the wiring harness beneath the vehicle for scuffing against the driveshaft or floorboard.
- Inspect the exhaust pipe after the catalytic converter for rust holes.
- Replace the downstream 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 P0137 is triggered when the post-catalyst oxygen sensor outputs less than 0.2 volts for over two minutes. Because downstream sensors sit exposed to rain, snow, and road debris underneath the floorpan, connector corrosion or severed wires are very common. It is safe to drive for a short time, but get it checked, though the CEL will stay illuminated.