P0301 on Ford: Causes, Symptoms and Fix Cost
Quick Answer
Not safe to drive
P0301 on a Ford means the engine computer has counted repeated misfires isolated to cylinder 1, the first cylinder in the firing order. Combustion in that cylinder is incomplete or absent, so the engine runs rough and loses power. The most common cause by far is a worn cylinder-1 spark plug or a failed ignition coil. A replacement plug costs only 10-40 EUR, so start there before chasing fuel or compression faults.
- Severity
- High · Misfire
- Typical repair cost, all makes
- €40-€1700
Connect a standard OBD2 adapter (Bluetooth LE on iPhone) to your Ford and Skanyx tells you what P0301 means on that engine, whether it is safe to keep driving, and what the fix should cost. Free on iPhone and Android.
Get Skanyx freeWhat does P0301 mean on a Ford?
The Quick Answer above is the generic definition. What follows is the model-specific detail for the Ford models that log P0301.
Ford Focus
2005-2022
The 1.0 EcoBoost is prone to coolant intrusion into cylinder 1 from a known degas-hose and head weakness, which can cause a misfire alongside coolant loss. On petrol Focus models, a failed cylinder-1 coil-on-plug or a worn plug is the everyday cause, while the 1.6 TDCi diesel can misfire from injector seal leaks near cylinder 1.
What causes P0301 on a Ford?
Beyond the generic causes listed on the main P0301 page, these are the patterns noted for Ford models:
Coolant intrusion into cylinder 1 on the 1.0 EcoBoost (degas hose / head)
: Ford Focus
Cylinder-1 injector seal leak on the 1.6 TDCi diesel
: Ford Focus
How to diagnose P0301 on a Ford with OBD2
- Read freeze-frame data to capture RPM, engine load, and coolant temperature at the moment the misfire was logged, which narrows cold-start versus load-related faults
- Swap the cylinder-1 ignition coil with the coil from cylinder 2, clear the code, and drive. If the misfire moves to cylinder 2 (now P0302), the coil is the fault
- Remove and inspect the cylinder-1 spark plug for electrode wear, carbon fouling, oil, or an out-of-spec gap. Compare it side by side with a plug from a healthy cylinder
- Confirm the cylinder-1 injector is clicking with a noid light or stethoscope, and check its resistance and wiring connector for an open or corroded pin
- Run a compression test on cylinder 1 and compare to its neighbours. More than a 10 percent drop, or a low reading that rises after adding oil, points to rings or valves
- Smoke-test or spray-test the cylinder-1 intake runner for a vacuum leak, and scan live fuel trims for a lean correction that tracks that cylinder
How much does P0301 cost to fix on a Ford? (EUR)
Estimated repair costs for P0301 in EUR, compiled across makes. Ford costs typically sit in the middle of each range.
| Repair | Parts Cost | Labor Cost | Total Estimate | DIY Difficulty |
|---|---|---|---|---|
| Replace spark plug (cylinder 1) | €10–€40 | €30–€80 | €40–€120 | Easy |
| Replace ignition coil (cylinder 1) | €40–€200 | €30–€100 | €70–€300 | Easy |
| Clean or replace fuel injector (cylinder 1) | €40–€180 | €60–€200 | €100–€380 | Moderate |
| Head gasket or valve repair | €150–€500 | €400–€1200 | €550–€1700 | Professional |
Prices estimated as of October 2026. Costs vary by region, vehicle, and shop.
Codes related to P0301
These codes are often seen alongside P0301 or point to related issues, on any make:
Looking for the full P0301 reference (all makes, full diagnosis flow, complete repair cost matrix)? See the main P0301 guide