What does it mean?
The diesel fuel system contains a low-pressure and high pressure side. The low pressure side consists of the tank, pump, filters, water separator, bleeder valves and necessary fuel lines. The high pressure side varies according to injection type, but typically consists of a high pressure pump and fuel rail. A typical common rail diesel fuel system The fuel volume control valve (FVCV) is found on high pressure pump on most modern common rail diesel engines.
It regulates the volume of fuel from the internal transfer pump to the high pressure pumping components. The valve adjusts the low pressure side of the system to meet the demands of the engine. The FVCV is a duty cycle controlled solenoid controlled by the PCM. One side of the solenoid receives battery power, and the other is intermittently grounded by the PCM. The combination of the FVCV and the fuel pressure control valve (FPCV) is used to correctly supply fuel to the engine.
The fuel pressure sensor monitors FVCV and FPCV operation and informs the powertrain control module (PCM) of any changes. A typical fuel volume control valve and high pressure pump The code P0004 stands for fuel volume regulator control circuit. The PCM monitors the state of the FVCV circuit and sets this code when it finds a high circuit.
Note: Circuit High Input codes are mostly caused by defective alternators that develop excessive voltages, although there may be other causes as well, such as short circuits that “leak” current into a particular system from other, unrelated systems that work on higher voltages. Note that in the case of short circuits that leak power into a control circuit, there is likely to be other, seemingly unrelated trouble codes present along with the code(s) being investigated.
Diagnosing a “high input” code will always involve a thorough testing of the charging system as a first step, followed by measures to isolate the system from all other possible sources of power during resistance, continuity, and reference voltage tests.