Fuel Volume Regulator Control Circuit / Open
The Powertrain Control Module (PCM) has detected an open circuit or lack of electrical continuity in the fuel volume regulator control circuit. This regulator is responsible for controlling the volume of fuel supplied to the high-pressure fuel pump in direct injection systems.
This code is highly urgent because a malfunctioning fuel volume regulator can prevent the engine from receiving adequate fuel, leading to stalling while driving or a complete inability to start the vehicle.
Common symptoms
- Illuminated Check Engine Light (MIL)
- Engine cranks but fails to start
- Engine stalling or hesitation during acceleration
- Noticeable lack of engine power or poor performance
- Limp mode activation restricting vehicle speed and RPM
Likely causes
- Disconnected, damaged, or corroded wiring and connectors in the fuel volume regulator circuit
- Faulty fuel volume regulator (FVR) solenoid or valve
- Open circuit in the wiring harness between the PCM and the regulator
- Poor electrical ground connection for the regulator circuit
- Internal failure of the Powertrain Control Module (PCM) (rare)
What to check before replacing parts
Perform a visual inspection of the wiring and connectors at the fuel volume regulator.
Look for: Look for disconnected plugs, frayed wires, backed-out pins, or corrosion that would cause an open circuit.
Check for battery voltage at the fuel volume regulator connector.
Look for: With the key on, engine off (KOEO), a lack of voltage indicates an open circuit in the supply wiring, a faulty relay, or a blown fuse.
Test the fuel volume regulator solenoid internal resistance.
Look for: Using a multimeter, measure the resistance across the regulator's terminals. An infinite reading (OL) indicates an internal open circuit, meaning the regulator must be replaced.
Test for continuity on the control circuit between the regulator and the PCM.
Look for: With the battery disconnected and both modules unplugged, measure resistance on the control wire. Infinite resistance indicates a broken wire in the harness.
Monitor actual versus commanded fuel rail pressure using a scan tool.
Look for: Look for actual fuel pressure readings that remain static or drop significantly below the PCM's target pressure during cranking, confirming the regulator is failing to supply the high-pressure pump.
This page explains the generic P0001 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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