MajorCommonEngine

Ford Focus: 1.5 EcoBoost R2DC cylinder deactivation P0302 misfire

1.5 EcoBoost R2DC cylinder deactivation P0302 misfire is a common engine fault on the Ford Focus on the 2018 onward cars, and we rate it major. Putting it right costs $450 to $2,800 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 37 documented faults on the Ford Focus.

Vehicle: Ford Focus
Engine: 1.5L
Years: 2018 onward
Fuel: petrol
System: Engine

This page covers the Ford Focus as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All Ford Focus faults37 documented faults on this model

What you are looking at

No photograph available

We do not hold a verified photograph for this fault yet. We would rather show none than show a picture of something else.

What goes wrong

The 1.5 EcoBoost R2DC engine with Ford's cylinder deactivation system (branded CylinderActivation) deactivates cylinder 2 during light-load cruise to save fuel. On reactivation, unburnt fuel and oil vapour that has pooled on the deactivated intake valves can cause a P0302 misfire event. Carbon deposits accelerated by the deactivation cycle also contribute. Ford released updated PCM calibrations to adjust deactivation thresholds and reactivation fuelling, but the underlying carbon fouling issue requires periodic direct-injection decarbonisation to fully resolve.

What you would notice

MIL (check engine) light with stored P0302 misfire code
Engine stumble or shudder when transitioning out of economy mode
Rough idle on light-load acceleration
Hesitation at 60-90 km/h under steady cruise throttle

How to check it

Where to look. Cylinder 2 (centre cylinder), intake valves, PCM calibration

Scan ECU for P0302 or cylinder deactivation system fault codes.
Confirm PCM calibration level against latest Ford TSB for R2DC CylinderActivation.
Remove cylinder 2 spark plug and inspect for fouling or oil traces.
Road test through steady light-throttle cruise at 80-100 km/h to provoke the fault.

What it costs to put right

$450 to $2,800 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

Ask the seller

“Has the PCM been reprogrammed to the latest calibration for cylinder deactivation?”
“Any stored or cleared misfire codes — particularly P0302?”
“Has the engine been decarbonised via walnut blasting or chemical soak?”
“When were the spark plugs last replaced?”

Now check the Ford Focus you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.

Ford Focus buyer questions

Is 1.5 ecoboost r2dc cylinder deactivation p0302 misfire serious on a Ford Focus?

We rate it major and common on the Ford Focus. The 1.5 EcoBoost R2DC engine with Ford's cylinder deactivation system (branded CylinderActivation) deactivates cylinder 2 during light-load cruise to save fuel. On reactivation, unburnt fuel and oil vapour that has pooled on the deactivated intake valves can cause a P0302 misfire event. Carbon deposits accelerated by the deactivation cycle also contribute. Ford released updated PCM calibrations to adjust deactivation thresholds and reactivation fuelling, but the underlying carbon fouling issue requires periodic direct-injection decarbonisation to fully resolve.

How much does it cost to fix on a Ford Focus?

$450 to $2,800 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which Ford Focus years are affected?

Our research records this fault on the 2018 onward Ford Focus. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.

How do I check for it before I buy?

Scan ECU for P0302 or cylinder deactivation system fault codes. Confirm PCM calibration level against latest Ford TSB for R2DC CylinderActivation. Remove cylinder 2 spark plug and inspect for fouling or oil traces. Road test through steady light-throttle cruise at 80-100 km/h to provoke the fault. Look here: Cylinder 2 (centre cylinder), intake valves, PCM calibration