What Does P0004 Mean?
P0004 indicates a high voltage condition on the fuel volume regulator (FVR) control circuit. The ECM has detected that the FVR solenoid circuit voltage exceeds the expected maximum threshold. This typically points to an open ground circuit, a short to battery voltage in the wiring, or a stuck-open FVR solenoid. The engine may run at excessively high fuel rail pressure, causing hard starting, injector damage, and rough running.
Safety Warning
Excessively high fuel rail pressure can damage injectors, fuel rails, and seals, creating a potential fuel leak and fire hazard. The engine may also run extremely rich, causing catalytic converter damage. Do not continue driving — have this repaired immediately.
Common Causes
30%
Open ground circuit for the FVR solenoid, causing the control signal to float high
25%
Short to battery voltage in the FVR control wiring where it runs near ignition-switched power sources
25%
FVR solenoid mechanically stuck open, allowing maximum fuel flow regardless of ECM command
20%
ECM driver circuit latched high due to an internal fault, keeping the FVR circuit voltage elevated
Diagnostic Steps
1
With the FVR solenoid disconnected and key on, measure voltage at both terminals of the harness connector — one should show ECM command voltage and the other should show near 0V (ground). If both are high, the ground is open.
2
Check the FVR solenoid ground path with an ohmmeter from the ground terminal at the connector all the way to battery negative — resistance should be under 0.5 ohms.
3
Inspect the FVR wiring for chafing or melted insulation near ignition-switched power wires that could create a short to B+ voltage.
4
Monitor actual fuel rail pressure at idle — if it reads significantly higher than the commanded target (e.g., 1,500+ PSI over target), the FVR valve is mechanically stuck open.
5
Command the FVR solenoid through various duty cycles using a bidirectional scan tool and verify fuel rail pressure responds correctly to each command step.
Estimated Repair Cost
$150 - $900
Parts + labor, varies by vehicle and location
P0004 indicates a high voltage condition on the fuel volume regulator (FVR) control circuit. The ECM has detected that the FVR solenoid circuit voltage exceeds the expected maximum threshold. This typically points to an open ground circuit, a short to battery voltage in the wiring, or a stuck-open F...
The most common cause of P0004 (Fuel Volume Regulator Control Circuit High) is: Open ground circuit for the FVR solenoid, causing the control signal to float high
Typical repair costs for P0004 range from $150 to $900, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Excessively high fuel rail pressure can damage injectors, fuel rails, and seals, creating a potential fuel leak and fire hazard. The engine may also run extremely rich, causing catalytic converter damage. Do not continue driving — have this repaired immediately.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0004 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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