P0137: O2 Sensor Circuit Low Voltage (Bank 1 Sensor 2)

What does P0137 mean?

The downstream (after-converter) oxygen sensor on bank 1 is reading low voltage for too long, which looks like a constantly lean exhaust. Sensor 2 is the downstream sensor, mounted after the catalytic converter; it mainly watches how well the converter is working and has little effect on fuel mixture.

Generic OBD-II definition: O2 Sensor Circuit Low Voltage (Bank 1 Sensor 2). Confirm applicability in your vehicle service information.

Common causes

• Exhaust leak ahead of the sensor letting in outside air
• Signal wire shorted to ground
• Sensor failed low
• Engine actually running lean

Symptoms

• Check engine light
• Usually no change in driveability

Can I keep driving with P0137?

Severity: Low Usually safe to keep driving, but get it checked.

If the check engine light is flashing or the car runs badly, stop driving and have it checked.

Typical fixes

• Check for exhaust leaks around the converter and flex pipe
• Check for lean codes (P0171/P0174) that point to a real lean condition
• Inspect wiring for chafing against the exhaust or body
• Replace the sensor if leaks and wiring check out