P0177 fault code: Fuel Composition Sensor Circuit Range/Performance

P0177 means “Fuel Composition Sensor Circuit Range/Performance” — a fuel and air metering fault in the powertrain.

Can I DIY?

Professional-only boundary. Not DIY: range/performance on a composition sender needs workshop data.

Do not DIYReviewed page boundary

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 P0177

Do not drive. The fuel-composition sensor is producing a value the computer treats as implausible — not simply high or low, but outside the performance window for that sender.

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

  • Fuel Composition Sensor Circuit Range/Performance: Number plate
  • Fuel Composition Sensor Circuit Range/Performance: Exact code P0177 and whether P0176/P0178/P0179 are also stored
  • Fuel Composition Sensor Circuit Range/Performance: Any recent fuel-system or tank sender work
P01xxFuel and air metering
MOT fail riskif the warning light stays on

What does P0177 mean?

P0177 is a generic (SAE standard) powertrain code reported by your car’s engine control unit. It sits in the P01xx block, which covers fuel and air metering. The stored description is “Fuel Composition Sensor Circuit Range/Performance”. The code itself tells you which circuit or system tripped the fault — not always the exact part that failed.

Will P0177 fail an MOT?

An illuminated engine management light is a Major defect at MOT (automatic fail) until the fault is repaired and the light stays off.

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.

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.
P0100Mass or Volume Air Flow Circuit P0101Mass or Volume Air Flow Circuit Range/Performance P0102Mass or Volume Air Flow Circuit Low Input P0103Mass or Volume Air Flow Circuit High Input P0104Mass or Volume Air Flow Circuit Intermittent P0105Manifold Absolute Pressure/Barometric Pressure Circuit P0106Manifold Absolute Pressure/Barometric Pressure Circuit Range/Performance P0107Manifold Absolute Pressure/Barometric Pressure Circuit Low Input

P0177 — quick answers

Is it safe to drive with P0177?

Do not drive. P0177 has no verified driving guidance. Do not drive until a workshop has checked the sender's range. A performance fault is not the same as the low-circuit store P0178 or the high-circuit store P0179.

Will P0177 fail my MOT?

An illuminated engine management light is a Major defect at MOT (automatic fail) until the fault is repaired and the light stays off.

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.