P0001

Fuel Volume Regulator A Control Circuit/Open

Fuel delivery Generic OBD-II High

What it means

P0001 means the ECM has detected an open in the control circuit for fuel volume regulator A — the valve that meters how much fuel the high-pressure pump delivers, common on diesel and direct-injection engines. With the circuit open, the ECM can't regulate fuel pressure, which can cause hard starting, low power, or even a no-start on affected systems.

High

Can I keep driving? Possibly not reliably — an open fuel-volume-regulator circuit can leave the ECM unable to control fuel pressure, causing hard starting or a limp-mode power loss, so get it diagnosed before it strands you.

Real-world scan data

Seen in

1,929

scans in the past year

Found in

0.3%

of scans

0.5%

of scans that found faults

Appears alongside · share of P0001 scans

P0683in 30.6% of scans

P0110in 28.6% of scans

P0100in 20.9% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
Hard starting or extended cranking
Reduced power or limp mode
Rough idle or hesitation
Decreased fuel economy

Common causes

Most likely first

Open or shorted wiring/connector in the fuel volume regulator control circuitLikely
Failed fuel volume regulator (solenoid)Common
Corroded or loose connector at the regulatorCommon
Failed ECM or regulator driver (rare)Less often

How to diagnose & fix

Work through it in order

Scan for freeze-frame data and confirm the code.
Inspect the regulator connector and wiring for opens, chafing, or corrosion.
Measure the regulator solenoid resistance and check for power and ground.
Repair wiring or replace the regulator as indicated.
Clear and retest; only consider the ECM if the circuit checks good.

FAQ

Quick answers

Is it safe to drive with P0001?+

Risky — the engine may start and run, but an uncontrolled fuel-pressure circuit can drop you into limp mode or a no-start without warning. Diagnose it promptly.

Can I just clear P0001?+

It comes back as soon as the ECM re-tests the circuit, since clearing doesn't repair the open. Fix the wiring or regulator first.

Read & clear P0001 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX