P0185 fault code: Fuel Temperature Sensor B Circuit

P0185 means “Fuel Temperature Sensor B Circuit” — a fuel and air metering fault in the powertrain.

Can I DIY?

Professional-only boundary. Professional only: sensor B is a different circuit from 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 P0185

Do not drive. Fuel temperature sensor B has a circuit fault. This is the second fuel-temperature input, not sensor A and not the engine-oil temperature sender in the P0195 family.

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: Number plate
  • Fuel Temperature Sensor B Circuit: Exact code P0185 and any P0180 family codes
  • Fuel Temperature Sensor B Circuit: Whether the car has two fuel-temperature senders (if known)
P01xxFuel and air metering
MOT fail riskif the warning light stays on

What does P0185 mean?

P0185 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”. The code itself tells you which circuit or system tripped the fault — not always the exact part that failed.

Will P0185 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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P0185 — quick answers

Is it safe to drive with P0185?

Do not drive. We have no verified driving guidance for P0185. Do not drive until a workshop has checked the B circuit. Do not treat this as a copy of the A-circuit page.

Will P0185 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.