P0004: Fuel Volume Regulator A Control Circuit High
Do not keep driving
Expect starting trouble or reduced power. Diagnosis before further driving.
What this code means
Voltage on the regulator control circuit is higher than expected — typically a short to a voltage supply, or an open circuit that lets the line float high. The distinction from P0003 is useful: high normally points at the supply side or an open return path, low at a ground fault. Both end at the same place if the regulator itself has failed internally.
Likely causes
Start here
- Wiring shorted to voltage · moderate
- Open circuit in regulator control wiring · moderate
Less common
- Failed fuel volume regulator · moderate
- Corroded or loose connector · easy
Rare
- Control module driver failure · specialist
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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