P2279 on Porsche: How to Diagnose & Fix
Intake Air System Leak
1 Porsche model · 1 documented issue · $400-$1,200 repair
P2279 on Porsche by model: symptoms, diagnosis and fix
The air-oil separator in the crankcase ventilation system can fail, with the internal diaphragm tearing. This lets crankcase vacuum spike and draws engine oil into the intake, producing heavy blue/white exhaust smoke (often worst on cold startup or under load), oil residue in the intake tract, possible whistling/hissing from the engine bay, and lean/rich fuel-trim faults. Failures are documented on 718 flat-four cars, in some cases at very low mileage. Driving with a failed AOS risks oil consumption and, in severe cases, hydrolock/engine damage.
Common Symptoms
- Blue/white exhaust smoke, worst on startup or under load
- Oil residue in intake
- Whistling/hissing from engine bay
- Rough idle / fuel-trim faults
- Elevated oil consumption
- Check engine light
How to Fix
Replace the AOS (some owners fit upgraded units, especially for track use); inspect the intake for oil contamination and clear any stored fuel-trim codes. Address promptly to avoid runaway oil consumption.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Porsche 0PC115099B complete oil separator
Confirm exact submodel/VIN for 2025 and order one 9A210747300 seal separately.
- Genuine Porsche 9A210747300 oil-separator seal
2017-2024 Porsche 718 Cayman 2.0L and 2.5L turbo applications cataloged by the retailer; 9A210747300/9A2-107-473-00. It is a companion, not a stand-alone AOS repair.
- Genuine Porsche 9A210790400 AOS diaphragm
Confirm engine/VIN and do not use for a damaged separator housing or unresolved crankcase fault.
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Sources for this issue (3)
P2279 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 P2279 mean on a Porsche?
P2279 stands for "Intake Air System Leak." This code means the engine computer detected an air leak in the intake system downstream of the mass airflow sensor (unmetered air entering the engine). Because this air is not measured, the engine may run lean, idle roughly, or behave inconsistently. The computer flags it when fuel trims or airflow readings indicate more air is reaching the cylinders than the sensor accounts for. It is usually not an immediate safety issue but can cause drivability problems, poor fuel economy, and other related lean codes. On Porsche it is documented across 1 model: 718 Cayman.
What are the most common causes of P2279?
The most common causes of P2279 are: Cracked or loose intake hose / air duct after the MAF, Vacuum leak (hoses, gaskets, PCV), Loose or damaged intake manifold gasket, Faulty or dirty mass airflow sensor, Leaking throttle body gasket, Unseated or cracked intake boot clamp, Failed PCV valve or hose. The specific cause varies by vehicle.
How much does it cost to fix P2279 on a Porsche?
Published repair estimates on Porsche range from $400 to $1,200 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
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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.