P0403 fault code: Exhaust Gas Recirculation Control Circuit

P0403 means “Exhaust Gas Recirculation Control Circuit” — an auxiliary emission controls fault in the powertrain.

Can I DIY?

Professional-only boundary. Do not remove or clean the EGR valve from this page. Confirm the code, then book a garage.

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 P0403

Do not drive. The engine computer reports a fault on the EGR control circuit — the electrical path that commands the recirculation valve, not a measured flow figure. No verified drive rating: do not drive until a garage checks it.

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

  • Exhaust Gas Recirculation Control Circuit: Registration number
  • Exhaust Gas Recirculation Control Circuit: Exact code P0403 and any companion codes
  • Exhaust Gas Recirculation Control Circuit: Whether the engine management light is on
  • Exhaust Gas Recirculation Control Circuit: Any exhaust smell in the cabin
P04xxAuxiliary emission controls
MOT fail riskif the warning light stays on

What does P0403 mean?

P0403 is a generic (SAE standard) powertrain code reported by your car’s engine control unit. It sits in the P04xx block, which covers auxiliary emission controls. The stored description is “Exhaust Gas Recirculation Control Circuit”. The code itself tells you which circuit or system tripped the fault — not always the exact part that failed.

Will P0403 fail an MOT?

An illuminated engine management light is a Major defect at MOT 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.
P0400Exhaust Gas Recirculation Flow P0401Exhaust Gas Recirculation Flow Insufficient Detected P0402Exhaust Gas Recirculation Flow Excessive Detected P0404Exhaust Gas Recirculation Control Circuit Range/Performance P0405Exhaust Gas Recirculation Sensor 'A' Circuit Low P0406Exhaust Gas Recirculation Sensor 'A' Circuit High P0407Exhaust Gas Recirculation Sensor 'B' Circuit Low P0408Exhaust Gas Recirculation Sensor 'B' Circuit High

P0403 — quick answers

Is it safe to drive with P0403?

Do not drive. Driveability guidance is not available for this code — treat as do not drive until checked.

Will P0403 fail my MOT?

An illuminated engine management light is a Major defect at MOT 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.