Ford P0340

Camshaft position sensor circuit on Ford — failing CMP sensor on 1.6/2.0 TDCi and 1.0 EcoBoost wet-belt debris damaging the reluctor.

Ford P0340 — Camshaft position sensor circuit on Ford — failing CMP sensor on 1.6/2.0 TDCi and 1.0 EcoBoost wet-belt debris damaging the reluctor. Typical UK independent garage cost: £60–£2200.

What actually causes P0340 on a Ford

On the 1.0 EcoBoost, P0340 alongside any rough running is often early wet-belt failure — debris damaging the cam reluctor pattern. On 1.6 TDCi it's normally just a £40 sensor degrading with heat. Always check service history for the cambelt-in-oil change interval before condemning components.

Ford engines that log P0340

• 1.6 TDCi DV6 (Focus/C-Max/Fiesta)
• 2.0 TDCi (Mondeo/S-Max)
• 1.0 EcoBoost (Fiesta/Focus)
• 1.5/1.6 EcoBoost

How we diagnose P0340 on a Ford

1. Read live cam vs crank signal correlation
2. Inspect oil for belt debris (sump magnet / oil filter cut-open)
3. Test CMP sensor resistance / signal at the ECU pin
4. Confirm cambelt service interval against Ford's revised wet-belt schedule

The common misdiagnosis to avoid

P0340 on a high-mileage EcoBoost without a belt service is never just the sensor — replace the sensor and you'll be back in 3 weeks with timing failure.

Ford P0340 repair cost in the UK

Expect £60–£2200 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.

Service campaign / TSB note

Ford revised 1.0 EcoBoost wet-belt interval down to 100k/10yr (originally lifetime).

Bob's workshop tip

EcoBoost P0340 + black sludge in oil filler = wet-belt job, not a sensor. Quote correctly first time.

Codes usually seen alongside P0340 on Ford

• P0341
• P0016
• P0017

Symptoms drivers report with P0340

• The car cranks for ages before finally firing up (limp mode start).
• Engine suddenly cuts out while waiting at a roundabout or junction.
• A noticeable lack of 'grunt' or pick-up, feeling like the turbo isn't boosting.
• The rev counter bounces erratically or drops to zero while driving.
• The car smells of unburnt petrol because the ECU is guessing the fuel timing.

Repairs that clear P0340

• Replace cam sensor (cheap, common fix)
• Repair wiring loom or connector
• On chain-driven engines, check chain wear before condemning sensor

For the generic, all-makes explanation of this code — meaning, every known cause and UK cost bands — see our P0340 guide.

Reading P0340 on a Ford properly

A generic reader will show P0340 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 P0340 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 P0340 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.