P0033 fault code: Turbo Charger Bypass Valve Control Circuit

P0033 means “Turbo Charger Bypass Valve Control Circuit” — a fuel and air metering fault in the powertrain.

Can I DIY?

Professional-only boundary. Do not clamp boost hoses or unplug the bypass valve on a hot turbo.

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 P0033

Do not drive until checked. The turbocharger bypass-valve control circuit is faulty. Boost air may not be dumped or recirculated on command; this is not an oxygen-sensor or cam-timing code.

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

  • Turbo Charger Bypass Valve Control Circuit: Registration number
  • Turbo Charger Bypass Valve Control Circuit: Exact code P0033 and any companion codes from the same scan
  • Turbo Charger Bypass Valve Control Circuit: Whether the engine management light is steady or flashing
  • Turbo Charger Bypass Valve Control Circuit: Any boost leak noise, overboost, or underboost already noticed
P00xxFuel and air metering
MOT fail riskif the warning light stays on

What does P0033 mean?

P0033 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 “Turbo Charger Bypass Valve Control Circuit”. The code itself tells you which circuit or system tripped the fault — not always the exact part that failed.

Will P0033 fail an MOT?

MOT testers fail a lit engine management light as Major until it stays off. P0033 is a turbo bypass-valve control circuit, not an HO2S heater code and not a cam-timing result.

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.
P0001Fuel Volume Regulator Control Circuit/Open P0002Fuel Volume Regulator Control Circuit Range/Performance P0003Fuel Volume Regulator Control Circuit Low P0004Fuel Volume Regulator Control Circuit High P0005Fuel Shutoff Valve 'A' Control Circuit/Open P0006Fuel Shutoff Valve 'A' Control Circuit Low P0007Fuel Shutoff Valve 'A' Control Circuit High P0008Engine Position System Performance

P0033 — quick answers

Is it safe to drive with P0033?

Do not drive until checked. We have no verified driving guidance for P0033. Treat as do not drive until checked. Do not clamp or disconnect boost hoses to 'test' the bypass valve.

Will P0033 fail my MOT?

MOT testers fail a lit engine management light as Major until it stays off. P0033 is a turbo bypass-valve control circuit, not an HO2S heater code and not a cam-timing result.

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.