P0074 fault code: Ambient Air Temperature Sensor Circuit Intermittent

P0074 means “Ambient Air Temperature Sensor Circuit Intermittent” — a fuel and air metering fault in the powertrain.

Can I DIY?

Professional-only boundary. Describe the flicker to the garage; do not chase an intermittent bumper plug yourself.

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 P0074

Do not drive. The outside-air temperature signal is dropping in and out instead of sitting at a hard high or low. Climate and any engine strategy that samples ambient can see the value jump between samples.

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

  • Ambient Air Temperature Sensor Circuit Intermittent: Registration number
  • Ambient Air Temperature Sensor Circuit Intermittent: Exact code P0074 and any companion codes
  • Ambient Air Temperature Sensor Circuit Intermittent: Whether the engine management light is steady or flashing
  • Ambient Air Temperature Sensor Circuit Intermittent: Whether the outside-temp reading flickered over bumps or in rain
P00xxFuel and air metering
MOT fail riskif the warning light stays on

What does P0074 mean?

P0074 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 “Ambient Air Temperature Sensor Circuit Intermittent”. The code itself tells you which circuit or system tripped the fault — not always the exact part that failed.

Will P0074 fail an MOT?

If the engine management light is on during the MOT, it is a Major fail even when the ambient reading only drops out sometimes.

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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P0074 — quick answers

Is it safe to drive with P0074?

Do not drive. We have no verified driving guidance for P0074. Intermittent ambient-circuit faults are ungraded — treat as do not drive until checked, because the lamp may be covering more than a display glitch.

Will P0074 fail my MOT?

If the engine management light is on during the MOT, it is a Major fail even when the ambient reading only drops out sometimes.

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.