P0108 fault code: Manifold Absolute Pressure/Barometric Pressure Circuit High Input

P0108 means “Manifold Absolute Pressure/Barometric Pressure Circuit High Input” — a fuel and air metering fault in the powertrain.

Can I DIY?

Professional-only boundary. Read P0108; high MAP input is not a published boost-pipe job on this page.

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 P0108

Do not drive. The manifold or barometric pressure circuit is pegged high, so the computer may think the engine is under boost or at an impossible altitude.

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

  • Manifold Absolute Pressure/Barometric Pressure Circuit High Input: Registration number
  • Manifold Absolute Pressure/Barometric Pressure Circuit High Input: Exact code P0108 and whether a turbo or supercharger is fitted
  • Manifold Absolute Pressure/Barometric Pressure Circuit High Input: Companion boost or misfire codes
  • Manifold Absolute Pressure/Barometric Pressure Circuit High Input: Whether the car felt unusually strong or unusually flat
P01xxFuel and air metering
MOT fail riskif the warning light stays on

What does P0108 mean?

P0108 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 “Manifold Absolute Pressure/Barometric Pressure Circuit High Input”. The code itself tells you which circuit or system tripped the fault — not always the exact part that failed.

Will P0108 fail an MOT?

An illuminated engine management light is a Major defect at MOT until the fault is repaired and the lamp stays off. P0108 is a high manifold/baro circuit input, not an MOT power test.

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

P0108 — quick answers

Is it safe to drive with P0108?

Do not drive. We have no verified driving guidance for P0108 — treat as do not drive until checked. A high MAP input is not a turbo overboost diagnosis you should road-test to confirm.

Will P0108 fail my MOT?

An illuminated engine management light is a Major defect at MOT until the fault is repaired and the lamp stays off. P0108 is a high manifold/baro circuit input, not an MOT power test.

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.