(2015 registrations)
presentation
at test
defect group
The Ford Fiesta is the most-bought used car in Britain, with over 303,000 changing hands in 2025 alone. That volume means its failure pattern is exceptionally well documented. The MOT records every defect by category, so we can rank what genuinely goes wrong — and separate the items that fail a car from the advisories that warn you what is coming next.
Figures are derived from the DVSA anonymised MOT tests and results dataset, published under the Open Government Licence v3.0. Every MOT records the test outcome plus each defect as a coded “reason for rejection” or advisory.
Percentages are share of tests, not share of failures — so “2.6% tyre tread” means 2.6 in every 100 tests failed for that item. A single test can record several defects, so the columns do not sum to 100%.
Top MOT failure items
These are the defects that actually caused a Ford Fiesta (2015) to fail its MOT, ranked by how often they appear across all tests.
Most common MOT advisories
Advisories are the early-warning layer. They don’t fail the car, but they tell you what the next owner will be paying for — and they are the single most useful thing to read before you buy.
| Advisory item | Share of tests | What it means |
|---|---|---|
| Brake pads wearing thin | 13.9% | Fiesta pads are cheap — budget £120–£240 per axle. |
| Tyre worn close to legal limit | 12.4% | Small wheels keep replacement costs low. |
| Suspension bush deteriorated | 11.8% | Ties directly to the No.1 failure item. |
| Corrosion to brake pipes or underbody | 10.2% | Common on higher-mileage cars — watch it escalate. |
| Steering ball joint slight play | 7.1% | The precursor to the No.5 failure item. |
| Shock absorber light misting | 5.9% | Rear shocks usually go first. |
| Engine oil leak (not excessive) | 5.2% | Check the sump and filter housing. |
| Exhaust minor leak or corrosion | 4.4% | Rear box is the usual culprit. |
| Brake disc lipped or scored | 4.1% | Usually replaced with pads. |
| Wiper blade deteriorated | 3.6% | Cheap, but an MOT failure if it smears. |
Which system fails most
Grouping every recorded defect by vehicle system shows where the money goes on a ten-year-old Fiesta.
Across 2,189,486 MOT tests on all Ford Fiesta variants, the pass rate is 72.9%. Petrol cars pass at 73.7%, comfortably ahead of diesel at 68.0%. Median mileage at test is 108,822 miles and the average repair bill after a failure is around £108. Nearly half of failures — 48.8% — are safety items.
A 2015 car passes at 74.5%, above the model average because it is younger than much of the fleet: 2017 cars pass at 80.6%, rising to 86.4% for 2018.
Model averages describe the model. Enter the registration to see this car’s real MOT history, every recorded advisory, its mileage timeline and any finance, theft or write-off markers.
The 1.0 EcoBoost: cooling system and wet belt
This is the single most important thing to check on a 2015 Fiesta. The three-cylinder 1.0 EcoBoost is an excellent engine when maintained correctly, but it has two well-known weak points that have nothing to do with the MOT test.
- The cooling system degas hose can crack, causing rapid coolant loss, overheating and a warped cylinder head — the failure owners nicknamed “EcoBoom”.
- Ford issued a Field Service Action in March 2015 covering 44,682 UK cars, replacing affected cooling parts and adding a coolant level sensor with a driver warning.
- Confirm the FSA was completed. A car with the sensor fitted has had the work done.
- Indicative repair if it has already overheated: £1,500–£3,000+.
- The 1.0 EcoBoost uses a wet timing belt that runs in engine oil, not a chain.
- Ford’s WSS-M2C948-B oil specification is non-negotiable. Generic oil degrades the belt and is the most common cause of failure.
- Ask for stamped service history showing the correct oil. No history is a real risk here.
- Indicative belt replacement: £450–£800.
Known faults the MOT won’t catch
The MOT tests roadworthiness, not mechanical health. These are the expensive items owners actually report — costs are indicative UK independent-specialist ranges, not quotes.
Pre-purchase checklist
Work through this in order. The first few cost nothing and rule out most bad cars.
- Confirm the March 2015 Field Service Action was completed on the cooling system.
- Check for the coolant level sensor — its presence indicates the recall work was done.
- Demand oil history to WSS-M2C948-B spec. On a wet-belt engine this is the single most important document.
- Read the full MOT history for repeated suspension and steering advisories.
- If automatic, test the PowerShift box hard — from cold, in stop-start traffic, and on a hill.
- Listen for front-end knocking over bumps; bushes and ball joints are the top failure items.
- Check the temperature gauge behaves on a long drive, not just around the block.
- Budget for wear items — on the advisory data, assume pads, tyres or bushes within a year.
FAQs
Is a 2015 Ford Fiesta reliable?
Broadly yes for the running gear — the failure list is dominated by ordinary suspension, tyre and lighting wear rather than drivetrain faults. The caveat is the 1.0 EcoBoost cooling system and wet belt, both of which depend entirely on how the car was maintained.
What fails a Ford Fiesta MOT most often?
Worn suspension pins, bushes and joints, at 5.0% of all tests — roughly double the rate of the next item. Stop lamps, tyre tread and steering ball joints follow.
What is the Ford EcoBoost “wet belt” problem?
The 1.0 EcoBoost timing belt runs inside the engine in oil. Using oil that does not meet Ford’s WSS-M2C948-B specification causes the belt to break down, and the debris can block the oil pickup and destroy the engine.
Should I avoid the PowerShift automatic?
Not automatically, but test it thoroughly. The DPS6 dry dual-clutch gearbox is known for shudder and hesitation. A car with documented clutch pack or TCM replacement may actually be the safer buy.
Is the Fiesta expensive to run?
No — it is one of the cheaper cars to maintain. The average MOT repair bill is around £108, and parts and tyres are inexpensive because of the small wheel sizes.
A CarCheckReport covers MOT and advisory history, mileage anomalies, outstanding finance, insurance write-off records, stolen markers, import and scrapped status — using DVLA, DVSA and Experian data.