Fuel Volume Regulator Control Circuit High
The Powertrain Control Module (PCM) monitors the electrical circuit for the fuel volume regulator, which controls how much fuel enters the high-pressure fuel pump. Code P0004 is set when the PCM detects that the voltage in this control circuit is higher than the manufacturer's specified range, often indicating a short to power or an open circuit.
This code requires immediate attention because it directly affects fuel delivery. It can lead to engine stalling, a no-start condition, or potential damage to the high-pressure fuel system.
Common symptoms
- Illuminated Check Engine Light
- Engine stalling or dying unexpectedly
- Hard starting or complete no-start condition
- Lack of engine power or hesitation during acceleration
- Limp mode activation restricting vehicle speed
Likely causes
- Shorted to power wiring in the fuel volume regulator circuit
- Corroded, damaged, or loose electrical connectors
- Faulty fuel volume regulator (FVR) solenoid
- Open circuit in the FVR wiring harness
- Failed Powertrain Control Module (PCM)
What to check before replacing parts
Visually inspect the wiring harness and connectors for the fuel volume regulator.
Look for: Look for frayed wires, melted insulation, or corroded pins that could cause a short to voltage or an open circuit.
Disconnect the fuel volume regulator and check for voltage at the harness connector with the key on.
Look for: If voltage is present on the control ground side when it shouldn't be, there is a short to power in the wiring harness.
Measure the internal resistance of the fuel volume regulator solenoid using a multimeter.
Look for: Compare the resistance reading to the manufacturer's specifications; an infinite reading indicates an internal open, while a zero reading indicates an internal short.
Perform a continuity test on the control and power wires between the regulator and the PCM.
Look for: High resistance or no continuity indicates a broken wire or severe corrosion in the harness.
Test the PCM's ability to control the circuit using a bidirectional scan tool.
Look for: If the wiring and regulator test good but the PCM cannot command the regulator or shows a constant high voltage fault, the PCM may be faulty.
This page explains the generic P0004 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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