CKFCar Known Faults
ModerateAffected: 2011-201850,000–100,000 miles

Ford Focus Mk3 1.0 EcoBoost 125bhp — Ignition Coil Pack Failure

Coil packs break down internally with heat and age, causing severe misfires under load.

Severity

Moderate

DIY Difficulty

Easy

Est. Cost

£50–£150

OBD Codes

P0300P0301P0302P0303P0304
Component Diagram

Engine

Typical layout and location for the Engine assembly.

Engine diagram
Reference Illustration

Symptoms

  • Engine hesitates and jerks when accelerating hard
  • Flashing EML light during misfire
  • Rough, lumpy idle
  • P0301-P0304 fault codes

Root Cause

The insulation inside the pencil coil breaks down due to engine heat. The spark then jumps to the cylinder head instead of crossing the spark plug gap.

How To Fix

  1. Read OBD codes to identify which cylinder is misfiring (e.g., P0302 = Cyl 2).
  2. Swap the coil pack to another cylinder and re-read codes to confirm the coil is at fault.
  3. Replace coil pack (£30-60 each).
  4. Advised to replace spark plugs at the same time.

Estimated Repair Costs

Repair OptionEst. Cost (GBP)
DIY (parts only)£20–£60
Independent Garage£50–£150
Main Dealership£80–£240

Other Faults on This Variant

Timing Chain Stretch and Tensioner Failure

Critical
2011-201540,000–100,000 miles£600–£1200

The Focus Mk3 1.0 EcoBoost shares the same timing chain vulnerability as the Fiesta Mk7. Pre-2016 engines are the highest risk — chain rattle on cold start must be investigated immediately.

Coolant Loss from Integrated Exhaust Manifold

Severe
2011-201860,000–120,000 miles£500–£900

The 1.0 EcoBoost's unique integrated exhaust manifold/cylinder head design causes head gasket stress. Coolant loss without visible leaks is a known issue on higher-mileage Focus Mk3 examples.

Turbocharger Boost Leak from Intercooler Pipe

Moderate
2011-201850,000–120,000 miles£30–£150

Boost pressure leaks from the plastic intercooler pipes and clamp connections on the 1.0 EcoBoost are common. A leak causes a noticeable flat spot and loss of performance under boost.

Disclaimer: Repair cost estimates are indicative and based on community data. Always get a quote from a qualified mechanic before proceeding with any repair.