Technical Description of OBD-II Trouble Code
The circuit controlling the fuel volume regulator is experiencing high levels of control
What does that signify?
This diagnostic trouble code (DTC) is a generic powertrain code that is applicable to OBD-II equipped vehicles, including Ford, Dodge, Vauxhall, VW, Mazda, and others. While it is a generic code, the specific repair steps may vary depending on the make and model of the vehicle.
A P0004 is not a very common trouble code and is more frequently observed in common rail diesel (CRD) and/or diesel engine, as well as gasoline direct injection (GDI) equipped vehicles.
This code pertains to the electrical system as part of the fuel volume regulator system. Automotive fuel systems consist of various components such as the fuel tank, fuel pump, filter, lines, injectors, and more. One component in high pressure fuel systems is the high pressure fuel pump. Its purpose is to increase the fuel pressure to the very high pressure required at the fuel rail for the injectors. These high pressure fuel pumps have a low pressure side and high pressure side, along with a fuel volume regulator that controls the pressure. In the case of this P0004 code, it refers to an electrical reading that exceeds the expected parameters.
This code is related to P0001, P0002, and P0003.
Symptoms
Indications of a P0004 DTC may include:
Potential Causes
Possible causes of this engine code may include:
Possible Solutions
First, check for any known Technical Service Bulletins (TSBs) specific to your year/make/model. If there is a known TSB that addresses this issue, it can save you time and money during the diagnosis process.
Next, visually inspect the wiring and connectors related to the fuel volume regulator circuit and system. Look for any obvious breaks in the wires, signs of corrosion, etc. Repair as necessary.
The fuel volume regulator (FVR) is a two-wire device with both wires connected to the PCM. Do not apply direct battery voltage to the wires as it could damage the system.
For more specific troubleshooting steps tailored to your year/make/model/engine, refer to a factory service manual.
