Code Definition

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

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; a bank-specific fault, meaning it applies only to one cylinder bank of a multi-bank engine; 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 P0137 fault code is set when the Engine Control Module (ECM) detects a lower than expected voltage output from the oxygen sensor located in Bank 1, Sensor 2. This sensor is typically situated downstream in the exhaust system, after the catalytic converter. A low voltage signal from this sensor usually suggests that there is a higher than expected level of oxygen in the exhaust, which can be indicative of a lean mixture or an issue with the catalytic converter's efficiency. The causes of a low voltage output can include a faulty oxygen sensor, issues in the wiring or connectors, or possible...

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