Code Definition

P1031 — O2 Sensor Heater Control Circuit Problem

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

About P1031

P1031 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 P1031 is stored, the module has detected 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.

P1031 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

The Engine Control Module (ECM) controls and monitors the heater circuit of the upstream oxygen sensor (Bank 1, Sensor 1). The heater is a resistive element that quickly brings the sensor to its operating temperature of roughly 315 degrees Celsius so the ECM can enter closed loop fuel control sooner after a cold start. DTC P1031 sets when the ECM detects that heater circuit operation is outside the expected range, typically caused by an open or shorted heater element, a supply or control circuit fault, or excessive circuit resistance. Because the sensor takes longer to reach operating temperat...

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