P0003 means the engine control module saw the fuel volume regulator (FVR) control circuit at a lower voltage than it should be. P0001 is the general circuit or open code, P0002 range or performance, P0003 low, P0004 high. The fuel volume regulator is the solenoid on the inlet side of the high-pressure fuel pump that meters how much fuel enters the pumping chambers, and so how much pressure reaches the rail. Manufacturers also call it a fuel metering valve, suction control valve (Denso), or a pressure control valve; on engines where they call it a fuel pressure regulator, the same fault sets P0091 instead.
Severity: moderate to high. Can you keep driving? Not far. A control line stuck low usually means the solenoid is held in one state, and the pump either starves the rail or floods it. Expect hard starting, reduced power, stalling, or a limp mode. On a common-rail diesel the module protects the rail by cutting fueling; treat it as a tow if the engine will not run cleanly.
Which engines have a fuel volume regulator
Common-rail diesels above all: Ford 6.7 L Power Stroke (owners on the Power Stroke forums report this code by name), GM Duramax, Ram Cummins, VW TDI, Nissan and Toyota diesels. Also gasoline direct-injection engines whose pump has a metering valve. If the engine has a mechanical return-style pressure regulator and no high-pressure pump, it has no fuel volume regulator, and a scan tool showing P0003 should be re-read with the manufacturer's definitions.
What "circuit low" means on a two-wire solenoid
The module drives the solenoid with a pulse-width-modulated signal on one wire and returns it on the other, and it watches the voltage on the control line between pulses. A control line that sits at or near zero when it should be pulled up means:
- a short to ground somewhere between the module and the solenoid, or
- a shorted solenoid winding drawing far more current than designed, or
- a driver in the module that has failed shorted.
None of these is a pump that has worn out, and none is a fuel supply problem. Low rail pressure with a healthy solenoid circuit sets P0087, not P0003.
Causes, in the order they are found
A chafed control wire shorted to ground. The harness to a pump on a diesel runs low on the block, crosses brackets and sits in heat. A wire rubbed through against the block sets this code with a perfect solenoid. GM's harness chafing bulletins for the Duramax list the neighboring regulator codes for exactly this reason.
A connector with fuel or moisture bridging the terminals, or a terminal pushed into contact with the shell.
A shorted solenoid winding. Windings on a hot pump break down and short between turns; resistance reads well below specification.
A shared ground or supply fault when several actuators show codes at once.
The module driver, last.
A diagnostic order
- Record the freeze frame and companion codes. P0087 or P0088 beside it are consequences; other circuit codes beside it point at a harness.
- Open the pump connector and look for fuel, water, corrosion or a displaced terminal.
- Measure the solenoid across its pins: a low, finite resistance against the specification. Well below specification is a shorted winding.
- With the module disconnected, check the control wire for a short to ground: it should read open to the block and to battery negative. A reading near zero ohms is the chafe to find, and the wiggle test along the harness locates it.
- Check the return wire the same way, and check that neither wire is shorted to the other.
- Repair the wire or connector, or replace the solenoid or pump only if the winding measured shorted. Then clear the code and verify rail pressure follows the commanded value on a road test. Let the readiness monitors complete before an inspection.
Frequently asked questions
Can I drive with a P0003 code?
Only to a shop, and only if the engine runs cleanly. The module cannot meter the high-pressure pump with the regulator's control line shorted, and most calibrations cut fueling or refuse to start rather than risk rail pressure it cannot control.
Is P0003 the fuel pump?
It is the regulator solenoid on the high-pressure pump, and the code means its control line is stuck low. A wire shorted to ground or a shorted winding both do that. Measure the winding and check the wire for a short before replacing the pump, which is a major part on a diesel.
What is the difference between P0003 and P0087?
P0087 means rail pressure was measured too low. P0003 means the electrical control line to the regulator was pulled low. A P0003 fault can cause a P0087, but a P0087 alone with a healthy regulator circuit is a supply, filter, or pump problem, not this code.
How much does it cost to fix P0003?
A wire repair is usually under an hour or two. The regulator solenoid on pumps where it is sold separately is a moderate part; where it is not, the high-pressure pump is a major repair, which is why the winding and the wiring are measured first.
Related codes
- P0001 / P0002 / P0004: fuel volume regulator control circuit open, range or performance, high.
- P0090 to P0092: fuel pressure regulator 1 control circuit, the same solenoid under another name on many engines; see P0090.
- P0087 / P0088: fuel rail pressure too low or too high.
- P0191 to P0194: fuel rail pressure sensor circuit; see P0194.
The code number itself tells you the family and the domain; how to read an OBD2 code number explains what each character means.