Code Definition

P0137 — Oxygen Sensor Circuit Low Voltage B1 S2

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P0137

P0137 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P0137 is stored, the module has detected a signal or supply voltage lower than the expected operating range; and a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P0137 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The bank 1 sensor 2 oxygen sensor sits downstream of the catalytic converter and monitors converter efficiency rather than controlling fuel delivery. A zirconia sensor generates its own voltage across the element, producing near 0.1V when exhaust oxygen is high and approaching 0.9V when it is low, with a healthy downstream signal normally resting steady around 0.6V to 0.7V behind a working converter. P0137 sets when the ECM sees that signal held below the lower threshold, commonly under about 0.2V, for a calibrated period. A persistently low reading means the ECM is being told the exhaust cont...

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