OBD2 code P0004 is defined as “Fuel Volume Regulator Control Circuit High,” signaling an electrical issue within the fuel volume control system where the circuit is receiving too high of an electrical input.
This can lead to various performance issues, such as rough idling, hesitation during acceleration, occasional power loss, or even stalling. It’s a critical alert because it indicates that the fuel system is not operating within its optimal range, potentially leading to inefficient fuel use and reduced engine performance.
P0004 quick overview
| Meaning | P0004: Fuel Volume Regulator Control Circuit High |
| Is it serious? | Yes, it impacts engine performance and fuel efficiency, leading to potential stalling or power loss. |
| Possible causes | – Faulty fuel pressure regulator – Damaged or corroded wiring harness – Faulty fuel pressure sensor – Issues with the fuel pump relay or fuse |
| How to diagnose? | Inspect the fuel pressure regulator for signs of malfunction or damage. Check the fuel pump relay and fuse for any issues that could affect fuel delivery. Perform a fuel pressure test to diagnose any problems affecting fuel delivery to the engine. Inspect the wiring harness for signs of damage or corrosion that could affect circuit voltage. Check the fuel pressure sensor for proper operation and accuracy in reading fuel pressure. |
P0004 Meaning
When your car flags up a P0004 code, it’s hinting at a hiccup in the electrical system that controls how much fuel gets pumped to your engine. Imagine trying to fill a glass with a hose that’s blasting water too forcefully – similarly, too much electrical signal might be telling your fuel system to deliver fuel under higher than needed pressure.
This can make your engine act up, showing symptoms like rough runs or unexpected stalls. The fuel system’s smooth operation is crucial for your car’s efficiency and power, so pinpointing and fixing the source of this high circuit signal is key to getting everything running smoothly again.
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How to fix P0004 – learn from mechanics
I looked into P0004 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.
Case #1: Honda P0004
Vehicle information 2012 Honda Civic LX 1.8L
Issue + repair history
- Vehicle intermittently stalls while driving
- Previous repairs include replacing the crankshaft position sensor and cleaning the throttle body
- Current symptoms include rough idling and occasional loss of power
Other OBD2 Codes + Test Results
- P0004 – Fuel volume regulator circuit high
Mechanic suggestions
- Check the fuel pressure regulator for any signs of malfunction
- Inspect the fuel pump relay and fuse for potential issues
- Perform a fuel pressure test to ensure proper fuel delivery to the engine
Final fix Upon inspection, it was discovered that the fuel pressure regulator was faulty, causing the high voltage reading in the circuit. Replacing the fuel pressure regulator resolved the issue, and the vehicle now runs smoothly without any stalling or loss of power.
Case #2: Ford P0004
Vehicle information 2008 Ford Focus SE 2.0L
Issue + repair history
- Vehicle experiences intermittent hesitation and jerking while accelerating
- Previous repairs include replacing the spark plugs and ignition coils
- Current symptoms include rough idling and occasional misfires
Other OBD2 Codes + Test Results
- P0004 – Fuel volume regulator circuit high
Mechanic suggestions
- Inspect the wiring harness for any signs of damage or corrosion
- Check the fuel pressure sensor for proper operation
- Perform a fuel pressure test to diagnose any issues with fuel delivery
Final fix After thorough diagnostics, it was determined that a faulty fuel pressure sensor was causing the high voltage reading in the circuit. Replacing the sensor resolved the issue, and the vehicle now accelerates smoothly without any hesitation or jerking.
Case #3: Chevrolet P0004
Vehicle information 2015 Chevrolet Malibu LT 2.5L
Issue + repair history
- Vehicle occasionally struggles to start and stalls shortly after starting
- Previous repairs include replacing the fuel pump and cleaning the fuel injectors
- Current symptoms include rough idling and occasional loss of power
Other OBD2 Codes + Test Results
- P0004 – Fuel volume regulator circuit high
Mechanic suggestions
- Check the fuel pressure regulator for any signs of malfunction
- Inspect the fuel pump relay and fuse for potential issues
- Perform a fuel pressure test to ensure proper fuel delivery to the engine
Final fix Upon inspection, it was discovered that a faulty fuel pressure regulator was causing the high voltage reading in the circuit. Replacing the fuel pressure regulator resolved the issue, and the vehicle now starts smoothly without any stalling or loss of power.
How to diagnose P0004
I made you an overview of solving this DTC, based on all the advice that was suggested by certified mechanics to address this issue in previously mentioned service cases.
| Diagnostic Step | Brief Explanation |
|---|---|
| Inspect the fuel pressure regulator | Check for any malfunctions that could cause excessive pressure or incorrect regulation of fuel to the engine. |
| Check the fuel pump relay and fuse | Ensure they are in good condition and functioning properly to support consistent fuel delivery. |
| Perform a fuel pressure test | Diagnose any discrepancies in fuel delivery that could be affecting engine performance. |
| Inspect the wiring harness | Look for damage or corrosion that could lead to high voltage readings in the circuit. |
| Check the fuel pressure sensor | Verify its operation and accuracy, as a faulty sensor could misinterpret fuel pressure levels. |
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I’ve made you a free PDF to choose the OBD2 scanner in 5 minutes.
✅ Which OBD2 scanner is best?
✅ Which type should you get (DIY, Pro, Hobby)
✅ What is the best scanner for the exact brand/feature (e.g best for BMW)
✅ How to get a Bi-Directional tool for as cheap as $40
✅ Discount coupons for scanners
PDF is 100% free and it is designed to help you pick a scanner in less than a few minutes! Not a boring 50-page guide.
Just tell me where to send it.
Hi, I am Juraj “Yuri” Lukacko. I got frustrated by unhelpful and scammy mechanics, so I decided to learn everything about car diagnostics myself. I test dozens of new car diagnostic tools every month along with learning new strategies to fix and customize cars. About Juraj Lukacko (Yuri)