P0090 fault code: Fuel Pressure Regulator 1 Control Circuit

Last updated · OBDCode UK editorial

P0090 means “Fuel Pressure Regulator 1 Control Circuit” — a fuel and air metering fault in the powertrain. Do not drive. The electrical control for fuel-pressure regulator 1 is faulty, so the computer cannot command that regulator. Rail pressure may wander because the control loop is broken, not because a spring was measured.

Can I DIY?

Do not DIY this repair. We do not publish DIY repair or strip-down steps for this code on this page. Read codes and observe only; leave the repair to a qualified garage.

Do not DIY this repairDIY boundary
ToolsSpecialist tools or workshop equipment — typically a professional garage job.

This fault is in the professional-only category. We do not publish strip-down or fitting steps on this page. Use a qualified garage.

Hot systems

Never open a hot coolant cap — pressure can scald you. Exhaust and catalytic converter get hot enough to burn and ignite debris. Stay clear of electric fans; they can run after shut-off.

P00xxFuel and air metering
MOT fail riskif the warning light stays on

What does P0090 mean?

P0090 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”. The code itself tells you which circuit or system tripped the fault — not always the exact part that failed.

Will P0090 fail an MOT?

MOT fails an illuminated engine management light as Major. Regulator 1 control circuit is not a MOT wiring heading of its own.

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.

What the MOT data says

No MOT certificate item corresponds to this code; MOT outcome data cannot be shown.

Related guides

Car diagnostic test cost: compare the scopeUK booking marketplaces currently publish diagnostic averages of about £52–£65. Engine management light on: steady or flashing?A steady engine management light means the computer has stored a fault. Drive with caution and get the code read. A flashing light is different — stop when it is safe.
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

P0090 — quick answers

Is it safe to drive with P0090?

Do not drive. P0090 has no verified driving guidance. The high-pressure fuel task that lists P0090 is Red with Stop. Do not drive. Do not back-probe a live regulator on a pressurised rail.

Can I fix P0090 myself?

Do not DIY this repair. We do not publish DIY repair or strip-down steps for this code on this page. Read codes and observe only; leave the repair to a qualified garage. Specialist tools or workshop equipment — typically a professional garage job.

Will P0090 fail my MOT?

MOT fails an illuminated engine management light as Major. Regulator 1 control circuit is not a MOT wiring heading of its own.

Fault-code identifiers are standard diagnostic facts. Their explanations and diagnostic guidance on this site are original editorial summaries, not reproduced SAE wording. MOT defect rules reflect the DVSA MOT inspection manual (2026). This page is general guidance for UK drivers, not a substitute for a professional diagnosis.