P00AF: How to Diagnose & Fix — Turbocharger/Supercharger Boost Control "A" Module Performance
2 vehicles · 1 makes · $50-$1,600 repair
How to diagnose and fix P00AF: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Ford F-150 · 2011–2025
P0299 sets when actual boost is about 4 psi or more below the commanded value for several seconds, dropping the truck into reduced-power limp mode (orange wrench light). On EcoBoost F-150s the most common causes are NOT the turbos themselves but cheaper upstream parts: a loose or popped cold-side intercooler boot/clamp, a torn orange rubber diaphragm inside the electronic turbocharger bypass (blow-off) valve, and cracked charge-pipe couplers. On 2024 F-150s with the 3.5L PowerBoost (Lariat/XLT/XL), Ford TSB 24-2264 says the upper air deflector can deform and restrict intake air to the right-side (passenger) turbocharger, causing turbo overspeed and damage (replacement deflector RL3Z-19E525-A); on 2021 PowerBoost trucks built on or before Sep 30, 2021, TSB 24-2257 traces P0299 to a restricted right air cleaner outlet pipe. Wastegate-actuator sticking can also contribute. Owners frequently — and wrongly — replace turbochargers when a smoke test would have found a hose or the bypass-valve diaphragm.
Common Symptoms
- Sudden loss of power / reduced-power limp mode
- Orange wrench warning light on the dash
- Hissing or whoosh under boost (boost leak)
- Hesitation on hard acceleration
- P0299 stored, sometimes intermittent
How to Fix
Always perform a high-pressure smoke test of the charge-air system before condemning the turbos. Reseat/replace the cold-side intercooler boot and clamps; inspect the electronic bypass valve for a torn diaphragm and replace if leaking. On 2024 3.5L PowerBoost trucks setting P0299, inspect the upper air deflector and replace it per TSB 24-2264 (RL3Z-19E525-A) if deformed; on 2021 PowerBoost trucks built on or before Sep 30, 2021, inspect the right air cleaner outlet pipe per TSB 24-2257. Check wastegate actuators for free movement. Only after leaks, the bypass valve, deflector, and wastegate are ruled out should a turbocharger be considered. A boot/clamp fix can be under $100; a turbo replacement runs into the thousands.
Sources for this issue (2)
Ford Edge · 2015–2024
The 2019 and later 2.0L EcoBoost uses an electronic wastegate actuator on the turbocharger (2015-2018 Edges use a vacuum-operated wastegate). Two related failures show up repeatedly: the actuator rod's retaining e-clip goes missing or the linkage works loose, producing a metallic rattle from the turbo area at idle and light throttle; and the electronic actuator itself fails or sticks, so the PCM cannot hold commanded boost and sets an underboost or actuator-performance code with a noticeable flat spot under acceleration. On 2019-2021 Edges the wastegate actuator fault often surfaces as P1464, a code whose description misleads shops toward the A/C system. Left alone, a flapping wastegate flap wears its bushings and eventually requires the whole turbo.
Common Symptoms
- Metallic rattle from the turbo at idle or light throttle
- Check engine light with underboost code
- Flat spot or lack of power on acceleration
- Whistle or hiss under boost
- Limp mode on hard acceleration
- Rattle worse on cold start
How to Fix
Inspect the wastegate actuator rod and the e-clip at the linkage first - a missing clip is cheap to fix and is a known cause of both the rattle and the codes. If the actuator is electrically failed or its commanded-vs-actual position is out of range on a scan tool data log, replace the wastegate actuator assembly (available separately from the turbo on these engines). Check the charge-air plumbing and the turbo bypass valve for leaks before condemning the turbo on an underboost code. Once the flap and bushings are worn enough to be sloppy, the turbocharger itself needs replacement.
Sources for this issue (6)
- Wastegate actuator/solenoid - 2.0L EcoBoost - Ford Edge Forumforum
- 2012 Edge Ecoboost Turbo Failure - 2.0L EcoBoost - Ford Edge Forumforum
- Ford SSM 49427 - 2.0L/2.3L EcoBoost lack of power, MIL - missing wastegate actuator e-cliptsb
- Ford SSM 50171 - inoperative wastegate actuator / missing e-clip / actuator rod damagetsb
- P1464 on 2019-2021 Ford Edge: Why an A/C Code Points to a Turbo Problemarticle
- P0299 on 2015-2024 Ford Edge: Turbo Underboost Causes and Fixesarticle
Ford F-150 · 2011–2024
Both the 3.5L and 2.7L EcoBoost turbos use exhaust wastegates whose actuator arm/linkage develops play as the bushings wear. The result is a distinctive metallic rattle — most noticeable for the first ~30-60 seconds after a cold start and at light throttle — coming from the turbo area. It is a common EcoBoost complaint because it sounds alarming, but it is usually a wear/NVH issue rather than an immediate failure. Ford has issued TSBs: 3.5L wastegate-rattle bulletins and a 2025 TSB for 2024 2.7L trucks (built on/before Oct 4, 2024) where a missing wave spring between the wastegate actuator lever arm and the turbine housing causes the rattle on both turbos.
Common Symptoms
- Metallic rattle from turbo area on cold start (~30-60 sec)
- Rattle at light throttle / tip-in
- Noise diminishes once engine warms
- No performance loss in early stages
How to Fix
Confirm the noise originates at the turbo wastegate (not the timing chain or cam phasers). Per Ford's 2.7L TSB, the repair is installing wave springs between the wastegate actuator lever arms and turbine housings on both turbochargers. On 3.5L trucks, Ford TSB 20-2016 (2017 F-150) installs a wastegate linkage spring washer kit (HL3Z-9G488-C) on both actuators; actuators with excessive arm play beyond that may need a new wastegate actuator or, in severe cases, turbocharger replacement under warranty. Often deferred if purely cosmetic noise. Wave-spring/actuator repair typically $150-$600; turbo replacement is far more but usually warranty-covered when within coverage.
Sources for this issue (2)
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P00AF code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P00AF mean?
P00AF stands for "Turbocharger/Supercharger Boost Control "A" Module Performance." The PCM uses a boost control module/solenoid ('A') to command the turbocharger or supercharger to the requested boost level. This code sets when the actual boost response does not match the commanded value, indicating the boost control 'A' module or its mechanical linkage is not performing correctly.
What are the most common causes of P00AF?
The most common causes of P00AF are: Faulty boost control solenoid/module, Sticking wastegate or variable-vane mechanism, Boost/vacuum leak in control lines, Wiring or connector faults, Restricted charge-air path or failing turbo. The specific cause varies by vehicle.
How much does it cost to fix P00AF?
Repair costs for P00AF range from $50 to $1,600, depending on the vehicle and root cause.
Which vehicles are affected by P00AF?
Au7o has documented P00AF across 2 vehicle models from 1 manufacturers: Ford.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.