P2C03: Low-side ground-short diagnosis in fuel regulator D control

P2C03 is the low-side short-to-ground check for the fuel-quantity control-valve driver in this source. Its failure observation is low voltage during the driver's off state. That command-state relationship matters: a low signal is not interpreted independently of what the output stage is supposed to be doing.

An event-based circuit decision

The table lists twenty events and a one-trip response. It also references battery voltage, engine speed, basic enabling criteria and diagnostic inhibitors. Twenty events should not be relabelled as twenty seconds; the controller is qualifying electrical observations associated with its diagnostic process.

The nearby open-circuit entry also mentions low off-state feedback, but describes a different electrical diagnosis. That is a warning against identifying the exact wiring defect from one uncontextualized voltage reading. The matching service routine must explain how the driver distinguishes those conditions.

Separate the electrical fault from fuel delivery

Preserve the reported driver state and command context alongside any pressure complaint. P2C03 is not evidence that pressure was necessarily too high or too low at the time; it reports the circuit classification. A regulator performance code requires its own interpretation.

The summary's impedance descriptions are not an instruction to measure across a connected controller or to apply power externally. Fuel and driver-circuit tests require the application's safe access and isolation procedure. Verification should confirm that the event-based electrical diagnostic completes without the low-side ground-short report, while avoiding assumptions based solely on an apparently normal idle pressure.

Source and applicability

2025 GM 07A-2 documented monitor only; module and calibration applicability must be matched to the vehicle. The application-matrix filename join remains unresolved; no model or engine fitment is inferred. GM PDF, page 739.