P0002 means the engine control module commanded the fuel volume regulator (the metering valve on the high-pressure fuel pump) and measured a response outside its expected range: too slow, too small, or inconsistent with the commanded value. P0001 is the circuit or open code, P0003 low and P0004 high; those three are electrical. P0002 is a performance code: the circuit passed, the behavior did not. Chrysler's definition on some vehicles reads "fuel quantity regulator 1 control circuit performance."
Severity: moderate. Can you keep driving? Carefully. A regulator that responds late lets rail pressure overshoot or undershoot, which shows as hesitation, surging, hard starting or reduced power. The module usually keeps the engine running with limits. Drive to a shop if it runs cleanly.
What the Giulia bulletin shows
FCA's bulletin 18-027-20 (March 2020) for the 2017 to 2018 Alfa Romeo Giulia with the 2.0 L turbo is a PCM flash that addresses a long list of codes, and P0002 (fuel quantity regulator 1 control circuit performance) is on it, beside P062A (fuel pump control performance), P0441 and P0440 (EVAP flow), P0128 (thermostat) and others. When a performance code appears on a vehicle with a flash bulletin that names it, the calibration is the first suspect, because a performance monitor is a comparison between expected and measured behavior, and the expectation lives in software.
Causes, in the order they are found
A calibration that expects a faster or different response than the hardware gives, corrected by a flash, as on the Giulia.
A metering valve sticking from varnish or debris, responding late or partially. Common on diesels run on poor fuel or with a neglected filter.
A weak low-pressure supply that starves the valve so its response lags: a clogged filter or a tired lift pump.
Contaminated fuel, water or debris, working on the valve's spool.
A connector or harness with resistance that distorts the pulse-width control without opening the circuit.
The high-pressure pump worn, so the valve's action no longer produces the pressure change expected.
The module, last.
A diagnostic order
- Check for a flash bulletin for the vehicle naming P0002. On the 2017 to 2018 Giulia 2.0 L it is the first step.
- Record companion codes. P0087 or P0088 say what the pressure did; P0003 or P0004 alongside make it electrical after all.
- Watch commanded and actual rail pressure at idle, on a snap throttle and under load, and the regulator duty cycle. A duty that swings widely to hold a steady pressure is a valve or pump not responding cleanly.
- Check the low side: filter condition and interval, lift pump pressure.
- Inspect the connector and measure the solenoid's resistance against specification, and check the wires for resistance end to end.
- Check the fuel for water and debris, and the filter housing.
- Replace the metering valve or the pump only if the pressure test points there after the flash, filter and wiring have been ruled out.
Frequently asked questions
Can I drive with a P0002 code?
Carefully, to a shop, if the engine runs cleanly. Rail pressure control is imprecise while the regulator responds late, so expect hesitation and reduced power. Stalling or hard starting means stop driving it.
Is P0002 the same as P0003 or P0004?
No. P0003 and P0004 are electrical: the control line is stuck low or high. P0002 means the circuit is intact and the valve's response was wrong, which points at the valve sticking, the fuel supply, or a calibration.
Will a software update fix P0002?
On some vehicles, yes. FCA's 2020 bulletin for the 2017 to 2018 Giulia 2.0 L lists P0002 among codes corrected by a PCM flash. Check for a bulletin naming the code before replacing any part.
How much does it cost to fix P0002?
A flash is an hour at a dealer. A fuel filter is routine. A metering valve is a moderate part on pumps where it is serviceable; the pump itself is a major repair and comes last.
Related codes
- P0001 / P0003 / P0004: fuel volume regulator circuit open, low, high; see P0003.
- P0090 to P0092: fuel pressure regulator 1 control circuit; see P0090.
- P0087 / P0088: rail pressure too low or high; see P0087.
- P062A: fuel pump control circuit performance, on the same Giulia list.
The code number itself tells you the family and the domain; how to read an OBD2 code number explains what each character means.