What P0002 means
The fuel volume regulator (also called metering unit or suction control valve) is a solenoid valve on the inlet side of the high-pressure pump, used mainly on common-rail diesel engines.
How the engine computer detects it
The engine control module pulses it to set how much fuel the pump draws in and delivers to the rail, and in this way controls rail pressure. With P0002 the circuit is electrically intact, but command and effect do not match: the measured current does not fit the duty cycle, or rail pressure does not follow the regulator position plausibly. The cause is often mechanical, for example a sticking valve, rather than the wiring.
Written from public technical sources and not yet checked by a mechanic. How we write these pages
Symptoms
- Check engine light on
- Loss of power or limp mode
- Jerking or unstable idle
- Hard starting or stalling
Common causes
- Regulator sticking or worn due to dirt, debris or water in the fuel Most likely
- High resistance at connector or wiring causing wrong current Possible
- Low-pressure supply problem: clogged filter or air in the fuel Possible
- Rail pressure sensor reading wrong values Less likely
How to diagnose P0002
- Read every stored code with an OBD-II scanner. If misfire or fuel trim codes are there too, fix those first: they often cause this one.
- Inspect the parts involved: fuel volume regulator, high pressure fuel pump, fuel volume regulator wiring.
- Work through the causes above from most to least likely, cheapest checks first.
- Clear the code and drive a full drive cycle to confirm the repair held.
Vehicles that report P0002 most
| Vehicle | Years | Reports | Share | Median miles |
|---|---|---|---|---|
| Mercedes-Benz C250 | 2012–2014 | 5 | 58k |
Counts of owner complaints to the NHTSA that mention P0002 (9 in total), not failure rates: popular models get more complaints simply because more of them are on the road. Models with fewer than 3 complaints are left out.
Reading the code
- P
- Powertrain
- 0
- Generic (SAE) code
- 0
- Fuel and air metering, auxiliary emission controls
- 02
- Specific fault
Questions drivers ask
Can I drive with code P0002?
Drive gently and only as far as you need to. The engine computer may limit power to protect the engine, so avoid highways and heavy traffic until it's fixed. If the check engine light starts flashing, pull over.
Will my car pass an emissions inspection with P0002?
Probably not in states that test vehicles with an OBD-II scan: an emissions-related code that keeps the check engine light on is usually an automatic fail. Rules differ by state and county, so check yours.
Will P0002 clear by itself?
The light can go off after several drive cycles without the fault, but the code returns if the cause is still there. After a repair, the readiness monitors need a full drive cycle before an inspection.
This page is general information, not a substitute for a professional diagnosis. Repair costs are rough estimates for parts and labor and vary by vehicle and region.