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
- Smoke-test full intake including dump valve
- Inspect dump valve diaphragm — bench-test by mouth suction
- Check PCV hose to inlet for splits
- 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.