Code Definition

P1137 — O2 Sensor Low Voltage During Power Enrichment

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: GM

About P1137

P1137 is a manufacturer-specific powertrain diagnostic trouble code recorded for GM vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1137 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.

P1137 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

This General Motors specific code monitors the upstream oxygen sensor during Power Enrichment, the wide open throttle mode where the PCM deliberately commands a rich mixture for maximum power. Under Power Enrichment the upstream Heated Oxygen Sensor should read high voltage near 800mV to 900mV because the mixture is rich, so the PCM runs a rationality check expecting that response. P1137 sets when the sensor instead reads low voltage during Power Enrichment, indicating the sensor is biased lean, slow, or that the commanded rich mixture is not actually being delivered. The driver may notice a f...

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