Failed fuel volume regulator solenoid (both sources). Wiring or connector problem in the regulator circuit, such as a break, short or corrosion (both sources). Faulty fuel pressure sensor (RepairPal). Engine computer (PCM) problem, less likely (RepairPal).

Repair broken, shorted or corroded regulator wiring or connectors (both sources). Replace the fuel volume regulator solenoid if it fails testing (both sources); on many engines it is part of or mounted on the high-pressure pump, so check the service manual for your vehicle. Replace a faulty fuel pressure sensor if diagnosis points to it (RepairPal). Suspect the PCM only after the regulator and its circuit check out (RepairPal).

P0001⛽ Fuel system / high-pressure fuel pump volume regulatorStop and fix promptly

P0001: Fuel Volume Regulator Control Circuit/Open (Meaning, Causes, Fixes)

Q: What does P0001 mean?

P0001 means the engine computer has found an electrical problem, most likely an open circuit, in the control circuit of the fuel volume regulator on the high-pressure fuel pump. The usual causes are a failed regulator solenoid or damaged, loose or corroded wiring. Vehicles with high-pressure fuel systems (common rail diesels and, according to OBD-Codes.com, gasoline direct injection engines) use a high-pressure pump with a fuel volume regulator, a solenoid-operated valve the engine computer (PCM) switches on and off to control how much fuel the pump delivers to the rail. RepairPal explains that excess fuel is routed back to the tank and that a fuel pressure sensor is used to monitor how the regulator is performing. P0001 sets when the PCM sees an electrical fault in the regulator's control circuit, most likely an open circuit. OBD-Codes.com says P0001 is not a very common code and is seen more often on diesel and GDI engines. It is a generic OBD2 code, so exact repair steps vary by make and model. Related codes are P0002 (range/performance), P0003 (circuit low) and P0004 (circuit high).

Q: Can I keep driving with P0001?

Stop and fix promptly. RepairPal rates P0001 urgent, meaning it should be dealt with right away. OBD-Codes.com gives no rating, but lists a no-start and limp mode (reduced power) among the symptoms. Because the fault can leave you with little power or a stalled engine, get it diagnosed soon and avoid relying on the vehicle until it is fixed.

Reviewed 2026-10-24 · Based on 2 cited source(s)

What P0001 means

Vehicles with high-pressure fuel systems (common rail diesels and, according to OBD-Codes.com, gasoline direct injection engines) use a high-pressure pump with a fuel volume regulator, a solenoid-operated valve the engine computer (PCM) switches on and off to control how much fuel the pump delivers to the rail. RepairPal explains that excess fuel is routed back to the tank and that a fuel pressure sensor is used to monitor how the regulator is performing. P0001 sets when the PCM sees an electrical fault in the regulator's control circuit, most likely an open circuit. OBD-Codes.com says P0001 is not a very common code and is seen more often on diesel and GDI engines. It is a generic OBD2 code, so exact repair steps vary by make and model. Related codes are P0002 (range/performance), P0003 (circuit low) and P0004 (circuit high).

Severity: can I keep driving?

Stop and fix promptly

RepairPal rates P0001 urgent, meaning it should be dealt with right away. OBD-Codes.com gives no rating, but lists a no-start and limp mode (reduced power) among the symptoms. Because the fault can leave you with little power or a stalled engine, get it diagnosed soon and avoid relying on the vehicle until it is fixed.

Common symptoms

Check engine light on (both sources)
Engine performance problems or lack of power (both sources)
Limp mode (reduced power) (OBD-Codes.com)
Engine may not start (OBD-Codes.com)

Likely causes

Roughly most to least common, based on the sources below. Your vehicle may differ.

Failed fuel volume regulator solenoid (both sources)
Wiring or connector problem in the regulator circuit, such as a break, short or corrosion (both sources)
Faulty fuel pressure sensor (RepairPal)
Engine computer (PCM) problem, less likely (RepairPal)

Diagnostic steps you can do

⚠ Before you start

Work on a cool engine, parked on level ground with the parking brake set. Never work under a car supported only by a jack.

Check for technical service bulletins (TSBs) for your year, make and model, which can point straight to a known fix (both sources).
Note whether the code is current or only a history code, then clear it and see if it returns; RepairPal says P0001 can appear intermittently.
Visually inspect the wiring and connector at the fuel volume regulator for broken wires, corrosion or loose connections, and repair what you find (both sources).
Do not apply battery voltage directly to the regulator wires; OBD-Codes.com warns this can damage the system.

Typical fixes

Repair broken, shorted or corroded regulator wiring or connectors (both sources)
Replace the fuel volume regulator solenoid if it fails testing (both sources); on many engines it is part of or mounted on the high-pressure pump, so check the service manual for your vehicle
Replace a faulty fuel pressure sensor if diagnosis points to it (RepairPal)
Suspect the PCM only after the regulator and its circuit check out (RepairPal)

Repair costs vary widely by vehicle, region, parts brand and shop, so we don't quote prices. Get a written estimate after diagnosis.

🛠 When to call a pro

Measuring the regulator solenoid's internal resistance with a digital multimeter, or for a more accurate result, viewing its control signal on a digital oscilloscope (RepairPal)
Checking the regulator's power and ground circuits with a multimeter and tracing faults on the factory wiring diagram (RepairPal)
Following the factory service manual's troubleshooting steps for the specific engine (OBD-Codes.com)
PCM testing or replacement if everything else checks out

Where to buy

Plain search links. Always match parts to your exact year, make, model and engine.

OBD2 scanners on Amazon Parts at Advance Auto Parts catalog at RockAuto

FAQs

Can I keep driving with P0001?

It is not a good idea. RepairPal rates P0001 urgent, and OBD-Codes.com lists limp mode, lack of power and a no-start as possible symptoms. Get it diagnosed soon.

What is the fuel volume regulator?

It is a solenoid-controlled valve, usually on the high-pressure fuel pump, that the engine computer switches on and off to control how much fuel the pump sends to the fuel rail. Excess fuel goes back to the tank. P0001 is about the electrical control circuit for that valve, usually an open circuit.

How is P0001 different from P0002, P0003 and P0004?

All four are fuel volume regulator control circuit codes. P0001 points to an open circuit, P0002 to a range or performance problem, P0003 to a circuit reading low and P0004 to a circuit reading high.

Do the sources agree on the details?

Mostly. Both describe the regulator as part of a high-pressure fuel system, both name a failed regulator solenoid and wiring as causes, and both recommend checking TSBs and inspecting wiring first. RepairPal frames it as a common rail diesel system and also lists a bad fuel pressure sensor and the PCM as causes, while OBD-Codes.com includes gasoline direct injection engines and lists only the solenoid and wiring. They also describe the wiring differently: OBD-Codes.com says both of the regulator's wires go back to the PCM, while RepairPal says the circuit has power at all times and ground when the engine is running. Check the wiring diagram for your vehicle. RepairPal rates it urgent; OBD-Codes.com gives no severity rating.

Sources

Last reviewed 2026-10-24. Code definitions and repair steps can vary by manufacturer. Confirm with your vehicle's service information.