P0003 — Fuel Volume Regulator A Control Circuit Low

P0003: Fuel Volume Regulator A Control Circuit Low — what it means, the affected system and what to check before replacing parts.

Meaning, symptoms, causes and checks

Fuel Volume Regulator A Control Circuit Low. Basic catalogue definition; diagnostic details have not yet been reviewed.

Affected system: Powertrain

Symptoms

  • Check-engine warning illumination.
  • Hard/no start, unstable idle, poor acceleration or reduced power depending on the vehicle.
  • The engine may stall; symptoms alone do not identify the electrical root cause.

Possible causes

  • Short circuit, poor terminal contact or damaged wiring in the fuel-volume regulator control circuit.
  • Internal electrical fault of the fuel-volume regulator.
  • Supply/control circuit fault; ECU driver failure only after comprehensive electrical checks.

What to check

  • Confirm P0003, saving freeze-frame, related codes and battery voltage.
  • Locate the regulator from OEM instructions and inspect its connector, harness and applicable fuses.
  • Check for shorts to ground or supply and measure the command signal against vehicle-specific wiring data.
  • Measure regulator electrical characteristics to OEM specification; do not assume a universal resistance.
  • Where available, compare requested and actual fuel pressure and assess regulator and fuel feed operation.
  • Repair the demonstrated fault and check for recurrence; do not open high-pressure fuel hardware without approved procedures.

Also written as: P0003-00, P000300, PO003 (some scan tools add the fault-type byte, e.g. -00).