P0004 medium Severity

P0004: Fuel Volume Regulator Control Circuit High

The vehicle may experience rough idle, reduced engine power, increased fuel consumption, stalling, or fail to start under certain conditions.

Overview

OBD-II DTC P0004 is a generic powertrain code indicating a high signal or voltage reading in the fuel volume regulator control circuit, typically caused by regulator failure, wiring issues, or electrical faults affecting fuel delivery.

Common Symptoms

  • Malfunction indicator light (check engine light) illumination
  • Reduced engine power or limp mode
  • Rough or uneven idle
  • Increased fuel consumption
  • Vehicle may stall or fail to start

Most Common Causes

Faulty fuel volume regulator (FVR) solenoid high

Internal failure or short in the regulator solenoid can cause high circuit voltage readings.

Wiring harness damage or poor electrical connections high

Corrosion, shorts, or breaks in the wiring between the FVR and PCM can produce high voltage signals.

Faulty Powertrain Control Module (PCM) driver circuit medium

Rare but possible; PCM output driver may malfunction, interpreting signals incorrectly.

Fuel pressure sensor or related component malfunction medium

Incorrect sensor feedback can cause the control circuit to operate outside expected ranges.

Diagnostic Steps

  1. Connect an OBD-II scanner to read and confirm the P0004 code and check for additional codes.
    Expected: P0004 present; possibly related codes regarding fuel system or pressure sensors.
    Interpretation: Confirms relevant trouble codes and helps identify whether multiple systems are affected.
  2. Visually inspect the fuel volume regulator electrical connector and wiring harness.
    Expected: No corrosion, frayed wires, bent pins, or loose connections.
    Interpretation: Damaged wiring or connectors can cause false high voltage readings and should be repaired before further testing.
  3. Using a multimeter, measure voltage and continuity in the fuel volume regulator control circuit.
    Expected: Voltage within manufacturer specified range; continuity with no shorts.
    Interpretation: Abnormal voltage or lack of continuity indicates wiring or component faults affecting circuit behavior.
  4. Test the resistance of the fuel volume regulator solenoid with the connector disconnected.
    Expected: Resistance within the expected ohm specification for the component.
    Interpretation: Out-of-range resistance suggests internal regulator failure requiring replacement.

Repair Solutions

Replace the fuel volume regulator (FVR) solenoid medium
Estimated Cost: $150 - $450

Component cost and labor vary by vehicle model; necessary when internal regulator failure is confirmed.

Repair or replace damaged wiring/connectors in the regulator circuit medium
Estimated Cost: $50 - $200

Costs depend on extent of harness repair or replacement required.

Reprogram or replace the PCM if its driver circuit is faulty hard
Estimated Cost: $400 - $1200

Only considered after eliminating other root causes; PCM replacement has high labor and part costs.

Common Misdiagnoses

Avoid these common diagnostic mistakes:

  • Diagnosing a clogged fuel filter or weak fuel pump as the primary issue without checking the regulator circuit
  • Misinterpreting related DTCs (e.g., P0001–P0003) as indicating identical root causes

Frequently Asked Questions

What is the definition of the P0004 engine code?

The P0004 code stands for Fuel Volume Regulator Control Circuit High. This generally indicates an issue with the Fuel System system.

Can P0004 cause engine damage?

With a severity level of medium, the vehicle may experience rough idle, reduced engine power, increased fuel consumption, stalling, or fail to start under certain conditions.

What are the symptoms of P0004?

Drivers often report: Malfunction indicator light (check engine light) illumination, Reduced engine power or limp mode, Rough or uneven idle when this code is present.

Potential causes for OBDII code P0004

It can be caused by several factors, most notably: Faulty fuel volume regulator (FVR) solenoid, Wiring harness damage or poor electrical connections, Faulty Powertrain Control Module (PCM) driver circuit.

How much does it cost to fix P0004?

Expect to pay around $200 if the issue is a Repair or replace damaged wiring/connectors in the regulator circuit, but up to $1200 if the Reprogram or replace the PCM if its driver circuit is faulty needs replacement.

Is the P0004 code specific to Ford?

This is a universal code. You might see P0004 on Ford, Chevrolet, Toyota, Honda, Nissan, or any other OBD-II vehicle.

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