P0188 fault code: Fuel Temperature Sensor B Circuit High

P0188 means “Fuel Temperature Sensor B Circuit High” — a fuel and air metering fault in the powertrain.

Can I DIY?

Professional-only boundary. Professional only: high on sensor B is not a licence to unplug sensor A.

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 P0188

Do not drive. Fuel temperature sensor B is reading electrically high. The fault is on the B-circuit high store, not the A-circuit high code P0183 and not a confirmed overheat of the fuel itself.

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

  • Fuel Temperature Sensor B Circuit High: Number plate
  • Fuel Temperature Sensor B Circuit High: Exact code P0188 versus P0183
  • Fuel Temperature Sensor B Circuit High: Fuel smell or heat-soak after shutdown
P01xxFuel and air metering
MOT fail riskif the warning light stays on

What does P0188 mean?

P0188 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 Temperature Sensor B Circuit High”. The code itself tells you which circuit or system tripped the fault — not always the exact part that failed.

Will P0188 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.
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P0188 — quick answers

Is it safe to drive with P0188?

Do not drive. P0188 has no verified driving guidance. Do not drive until a workshop has checked the high B-circuit. We will not borrow P0183's wording or invent a milder 'yes with care' rating.

Will P0188 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.