Boost control · Fault code

P00AF

Turbocharger / Supercharger Boost Control "A" Module Performance

Something in the boost-control chain is not performing the way the ECU expects. Manufacturers word this code quite differently, so what "module" means here depends on the engine.

Severity EXPERT Moderate — diagnose before it gets worse
Driveability EXPERT Drive with caution — the ECU is already protecting itself
Tuning EXPERT Do not tune a car storing this — fix it first

Check first — in this order

The order is the product. A list of "possible causes" is what every parts site publishes, and it is why people replace parts blindly. Steps marked by architecture belong to one boost design and are noise on the other.

  1. Find out what this code means on this engine before acting. The generic title covers a range of OEM strategies, and the component it points at is not the same on every manufacturer. EXPERT
  2. Read commanded against actual position where the engine reports both; the control loop usually logs this because it already knows it lost authority. EXPERT
  3. Check supply, ground and signal wiring to the control device before condemning anything. EXPERT
  4. Wastegated (petrol) Then the mechanism it is trying to move — linkage seizure, flapper binding with carbon. EXPERT
  5. Variable-geometry (diesel) Then the mechanism it is trying to move — vane travel and actuator authority. EXPERT

What this code does not license you to replace

  • That this is a wastegate actuator code. That is one OEM reading of it, not the definition.
  • That the module is faulty. A mechanism that will not move produces the same code from a healthy module.

Companion codes

Codes whose presence alongside P00AF changes the path.

P0299P0234P0243

Engines we cover that log this

EA888 Gen 3 Wastegated (petrol)BMW N54 Wastegated (petrol)BMW N55 Wastegated (petrol)
No workshop sign-off yet. The diagnostic order on this page has had a technical review of the knowledge model, performed by a model — not a manufacturer certification and not a mechanical inspection of any vehicle. No tuner has yet put their name to this ordering. Treat it as a reasoned starting point, confirm with measurement, and get a professional to sign off before you condemn a part.

Built by DMS Tuned

Stuck on P00AF? Send us the log.

DMS Tuned is a real ECU-tuning shop. If you have a boost/requested-vs-actual log, run it through the analyser first — then message us and we will read it with you before you spend money on parts.

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