P0091 fault code: Fuel Pressure Regulator 1 Control Circuit Low

Can I drive with P0091? — Do not drive

P0091 has no verified driving guidance and is not covered by the high-pressure fuel job's related codes (that list stops at P0090). Driveability is ungraded — treat as do not drive until checked. Do not open fuel pipes.

P0091 means “Fuel Pressure Regulator 1 Control Circuit Low” — a fuel and air metering fault in the powertrain.

Can I DIY?

Professional-only boundary. Do not open fuel pipes or borrow a P0090 repair path; book diagnosis.

Do not DIYReviewed page boundary

ToolsSpecialist equipment

This is the conservative boundary from the reviewed code record. This page has no frozen site-wide safety grade, so it does not publish a repair route.

What to tell the garage about P0091

Do not drive. The control circuit for fuel-pressure regulator 1 is reading low — often open or shorted to earth — so the regulator may not be driven. Rail pressure control can then fail on the electrical side.

Take these reviewed, code-specific details with you. They help the garage confirm the fault without turning this page into a repair procedure.

Fuel Pressure Regulator 1 Control Circuit Low: Registration number
Fuel Pressure Regulator 1 Control Circuit Low: Exact code P0091 and any companion codes
Fuel Pressure Regulator 1 Control Circuit Low: Whether the engine management light is steady or flashing
Fuel Pressure Regulator 1 Control Circuit Low: Whether P0090 or rail-pressure codes were stored with P0091

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Fault code: P0091 — Fuel Pressure Regulator 1 Control Circuit Low.
Can I drive: Do not drive. P0091 has no verified driving guidance and is not covered by the high-pressure fuel job's related codes (that list stops at P0090). Driveability is ungraded — treat as do not drive until checked. Do not open fuel pipes.
Question: What does this code mean for a UK car, is it safe to drive, what are the most likely causes, and what should I ask a garage to check before replacing parts?

For your garage

REPAIR BRIEF — prepared by the owner with obdcode.co.uk
Fault code: P0091 — Fuel Pressure Regulator 1 Control Circuit Low.
Drive guidance from obdcode.co.uk: Do not drive. P0091 has no verified driving guidance and is not covered by the high-pressure fuel job's related codes (that list stops at P0090). Driveability is ungraded — treat as do not drive until checked. Do not open fuel pipes.
Owner’s request: please diagnose before replacing parts, itemise diagnosis time separately, and quote before any work beyond diagnosis.

P00xxFuel and air metering

MOT fail riskif the warning light stays on

What does P0091 mean?

P0091 is a generic (SAE standard) powertrain code reported by your car’s engine control unit. It sits in the P00xx block, which covers fuel and air metering. The stored description is “Fuel Pressure Regulator 1 Control Circuit Low”. The code itself tells you which circuit or system tripped the fault — not always the exact part that failed.

Will P0091 fail an MOT?

A lit engine management light is a Major MOT fail. Circuit-low on regulator 1 is not a MOT named electrical item.

Before booking your test, check what usually fails on your car: see our MOT pass rates by make and model, built from 33.1 million DVSA tests.

P0001Fuel Volume Regulator Control Circuit/Open P0002Fuel Volume Regulator Control Circuit Range/Performance P0003Fuel Volume Regulator Control Circuit Low P0004Fuel Volume Regulator Control Circuit High P0005Fuel Shutoff Valve 'A' Control Circuit/Open P0006Fuel Shutoff Valve 'A' Control Circuit Low P0007Fuel Shutoff Valve 'A' Control Circuit High P0008Engine Position System Performance

P0091 — quick answers

Is it safe to drive with P0091?

Do not drive. P0091 has no verified driving guidance and is not covered by the high-pressure fuel job's related codes (that list stops at P0090). Driveability is ungraded — treat as do not drive until checked. Do not open fuel pipes.

Will P0091 fail my MOT?