P0137
O2 Sensor Circuit Low Voltage Bank 1 Sensor 2
Fuel & air metering (emissions)
Generic OBD-II
Medium
What it means
P0137 means the downstream oxygen sensor (Bank 1, Sensor 2, after the catalytic converter) is reporting a steadily low voltage. That sensor checks how well the converter is working rather than trimming fuel, so the car usually drives fine — the practical effects are a check-engine light and a failed emissions test until the sensor, wiring, or a nearby exhaust leak is sorted out.
Medium
Can I keep driving? Yes, the car drives normally — this is a downstream O2 sensor code, so the main effects are a warning light and a failed emissions test.
Common symptoms
What you'll notice
- Check-engine light on
- Will fail an emissions/smog test
- Little or no change in how the car drives
- Possible slight drop in fuel economy
Common causes
Most likely first
- Failed downstream (post-catalyst) oxygen sensorLikely
- Exhaust leak near the sensor pulling in fresh air (false lean reading)Common
- Wiring shorted to ground or a corroded connectorCommon
- Open or high-resistance signal circuitLess often
- Failed engine control module (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and inspect the Bank 1 Sensor 2 connector and wiring for damage or corrosion.
- Check for exhaust leaks upstream of the sensor, which can drive the voltage low.
- Back-probe the sensor signal circuit for a short to ground or an open.
- If wiring is good, replace the downstream O2 sensor.
- Clear the code and drive a full cycle to confirm it stays off.
FAQ
Quick answers
Is it safe to drive with P0137?+
Yes. Sensor 2 monitors the catalytic converter rather than controlling fuel, so the car drives normally — but you'll fail emissions until it's fixed.
Can I just clear P0137?+
It will return once the sensor is monitored again unless the sensor, wiring, or exhaust leak causing the low voltage is repaired.
Related codes
Often seen with P0137
Read & clear P0137 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX