P1031 (Chevrolet): HO2S Heater Current Monitor Control Circuit Sensors 1 — what it means, the affected system and what to check before replacing parts.
The monitoring circuit for the heater current of the front oxygen sensors (Bank 1 and 2, Sensor 1) is operating outside of expected parameters. Manufacturer-specific definition; confirm applicability in the service information for the exact vehicle.
Affected system: Powertrain