Error Code P0001 is described as Fuel Volume Regulator Control Circuit/Open, and is linked to issues with the electrical circuit connected to the fuel pressure regulator.


Error Code P0001 shows up when there’s an electrical problem that causes the fuel volume regulator to malfunction and open. It’s quite an unusual problem and likely intermittent.

This means the diesel fuel system contains both a low pressure and a high pressure side. The low pressure side includes the filters, pump, tank, bleeder valves, water separator, and the important fuel lines. The components of the high pressure side on will vary depending on the type of injection, but it usually includes a fuel rail and pressure pump.

Most modern common rail diesel engines have FVCV or fuel volume control valve as a key component of its high pressure pump. Its job is to regulate the volume of fuel to the high pressure pumping components from internal transfer pump. The valve meets the demands of the engine by adjusting the low pressure side.

This means the FVCV is a duty controlled solenoid by the PCM. It receives power from the battery on one side and ground to the other side from the PCM.

The PCM sets the Error Code P0001 when it finds a problem on the FVCV. And an open circuit means that the sensor or the component is being deprived of the reference voltage it needs to work properly.

Common Symptoms

  • Check Engine light is on
  • Affects the engine performance when driving
  • May causes the exhaust to
  • Possible stalling
  • No start condition
  • Lack of power
  • Inefficient fuel consumption

Possible Causes

Causes of this Error Code may vary, but the usual suspects are

  • Poor connections across electrical connectors
  • Broken wiring
  • Blow fuses
  • Loss of ground preventing flow of current
  • Faulty switches
  • Defective relays
  • Issues on the previously repaired wires
  • Or any sort of problem that compromises the current flow throughout the wiring system.

How to Check

The easiest way to diagnose this error is through an advanced scan tool code reader. Qualified technicians can easily read data from their advanced scan tools to determine when and how the problem occurs. This may include clearing the code to repeat testing and monitoring data.

Diagnosis may also require multiple tools, such as:

  • Advanced scan tools for reading ECM data values
  • Fuel pressure tester
  • Digital voltage meter (with attachment)

If after repeated tests you see code coming back, then you will have to inspect the connectors and wiring that connect to the fuel volume regular circuit and its system. You may refer to factory service manual for specific troubleshooting steps.

Many people resort to simply replacing the fuel pressure regulator when diagnosing this error code, however, this doesn’t guarantee successful repair as the error code may be caused by a different component(s).

Never spend money to replace your fuel pressure regulator if you’re not sure it’s what’s causing the error code. You must have your vehicle thoroughly checked, not just through visual inspection, but also using special equipment by a trained mechanic.

For electrical signals, it must be evaluated thoroughly using a scan tool and a voltage meter. This is to ensure that your vehicle is really in need of a fuel pressure regulator replacement, or if there are other problems that causes the error code.

How to Fix

Some of the most common fixes for this error code includes:

  • Analyzing the data from the ECM
  • Inspecting all items such as wiring and leaks, etc.
  • Replacing the trouble component, such as wiring

Parting Tips

Though quite an uncommon error code, P0001 must be properly addressed as it may cause drastic increase in fuel consumption of your vehicle, instability that may damage the engine, may compromise the catalytic converter (which can be an expensive repair) and prevent you from passing emission tests.

This is quite a tricky error code to diagnose and fix, thus, you must get the services of a professional technician to have it properly addressed.