Ford P2279

Intake air system leak on Ford — perished dump valve diaphragm or split silicone elbow on 1.0/1.5/1.6 EcoBoost.

Ford P2279 — Intake air system leak on Ford — perished dump valve diaphragm or split silicone elbow on 1.0/1.5/1.6 EcoBoost. Typical UK independent garage cost: £35–£280.

What actually causes P2279 on a Ford

P2279 means the ECU sees more air than it should at idle — on EcoBoost it's nearly always a perished dump-valve diaphragm or a split silicone elbow between the turbo and throttle. Smoke test in under 10 minutes.

Ford engines that log P2279

• 1.0 EcoBoost
• 1.5 EcoBoost
• 1.6 EcoBoost (Focus ST/Kuga)

How we diagnose P2279 on a Ford

1. Smoke-test full intake including dump valve
2. Inspect dump valve diaphragm — bench-test by mouth suction
3. Check PCV hose to inlet for splits
4. Verify oil filler cap seal not blown out

The common misdiagnosis to avoid

Don't replace the throttle body or MAF on P2279 — it's a mechanical leak 95% of the time. Smoke test first, every time.

Ford P2279 repair cost in the UK

Expect £35–£280 including parts and labour at an independent garage. Main-dealer quotes on Ford are usually higher for the same job, and the spread exists because the cheap cause and the expensive cause throw the same code — pay for the diagnosis before you pay for parts.

Bob's workshop tip

EcoBoost P2279 + sooty residue around dump valve = diaphragm. £45 part, 20 min fit.

Codes usually seen alongside P2279 on Ford

• P0171
• P0507
• P0299

Symptoms drivers report with P2279

• The car 'kangaroos' or jitters when you're cruising at 30mph in 3rd gear.
• A loud 'whooshing' or whistling sound, like a jet engine, when you boot it onto a dual carriageway.
• Car suddenly drops into 'Limp Mode' with 'Service Vehicle Soon' on the dash.
• Black smoke pouring out the back when you're trying to overtake.
• The idle hunts up and down slightly when you're sat at the traffic lights.

Repairs that clear P2279

• Smoke test
• Hose replacement

For the generic, all-makes explanation of this code — meaning, every known cause and UK cost bands — see our P2279 guide.

Reading P2279 on a Ford properly

A generic reader will show P2279 and nothing else. What matters is the freeze-frame data stored with it — engine speed, load, coolant temperature and fuel trims at the moment the fault was logged — plus whether any other module on the Ford has logged something at the same time. Codes rarely arrive alone, and the order they were stored in usually points at which one is the cause and which are the consequences.

Clearing P2279 without fixing it

Erasing the code resets the Ford's readiness monitors as well as the light. The fault returns on the next drive cycle if the cause is still there, and in the meantime the incomplete monitors can stop the car passing an emissions check. After a genuine repair, the car is driven until the relevant monitor completes before it is handed back.

Bob's Mechanical Repairs is an independent garage in Birnam, Dunkeld, Perthshire, with 32 years of Bob's experience on the tools. If P2279 is showing on your Ford, bring any scan results with you — we will read the live data ourselves, confirm which cause it actually is, and price the repair before any work starts.