P2279: How to Diagnose & Fix — Intake Air System Leak
8 vehicles · 5 makes · $50-$8,000 repair
How to diagnose and fix P2279: 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.
Porsche 718 Cayman · 2017–2025
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)
SEAT Leon · 2007–2012
The CAVD 1.4 TSI Twincharger (supercharger + turbo) in Leon Mk2 / Golf Mk6 / Scirocco / Touran is double-trouble: the EA111 timing-chain stretch issue AND supercharger magnetic-clutch failure. Combined repair if both fail is among the most expensive on the platform.
Common Symptoms
- cold start rattle
- whine from supercharger
- limp mode
- reduced power
How to Fix
Chain kit €700-€1,200. Supercharger clutch repair €350-€700 (rebuild) or new pulley €600-€1,000. Many independents recommend ditching the supercharger if budget-limited (remap removes its operation) — power drops but reliability improves.
Volkswagen Tiguan · 2009–2023
EA888 2.0 TSI engines use low-tension piston and oil control rings to reduce internal friction for fuel economy. Owners report the rings allow blow-by and let oil into the combustion chamber, so the engine burns oil far faster than a healthy engine should - in bad cases a quart every 1,000-1,500 miles. Volkswagen's own consumption standard is unusually permissive (roughly 0.5 quart per 600 miles), so dealers frequently declare a car 'within spec' after an oil consumption test even though the owner is topping up constantly. Consolidated class-action litigation over EA888 oil consumption was filed in the US covering Tiguan owners. Running low on oil compounds the problem because the timing chain tensioner and turbo bearings starve first.
Common Symptoms
- Low oil level warning between changes
- Adding a quart every 1,000-2,000 miles
- Blue smoke on startup or hard acceleration
- Fouled spark plugs
- Oil smell / oily intake tract
How to Fix
Start with an oil consumption test documented at the dealer to create a warranty record. Confirm the PCV valve / valve cover breather is not the actual leak path (a failed PCV diaphragm dumps oil into the intake and mimics ring wear) and check for a leaking turbo seal. If the PCV and turbo check out and consumption is genuine, the only durable repair is pulling the engine and replacing the pistons and rings with the revised parts. Interim management: check oil at every fuel stop, keep the level at full, and shorten oil change intervals to about 5,000 miles with 502.00-spec oil.
Sources for this issue (3)
Opel Zafira · 2005–2014
Volkswagen CC · 2009–2017
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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?
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.
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?
Repair costs for P2279 range from $50 to $8,000, depending on the vehicle and root cause.
Which vehicles are affected by P2279?
Au7o has documented P2279 across 8 vehicle models from 5 manufacturers: Audi, Opel, Porsche, SEAT, Volkswagen.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.