At a glance
How 10,100 first tests went in 2025.
- Passed first time
- 86 in every 100
- Did not pass first time
- 14 in every 1001,364 failed first-attempt tests
- The typical car
- 8 yearsabout 96,346 miles
- First tests counted
- 10,100
What failed most often
- Tyre tread depth (front)13 in every 100 failed tests
- Anti-roll bar linkage ball joint dust cover (front)11 in every 100 failed tests
- Windscreen wipers (front)10 in every 100 failed tests
How we count this. Data: UK MOT open data, 2025. Only Class 4 cars on their first MOT of the year are counted. A car that fails and is fixed at the test station still counts as a fail in the first-attempt rate. These are raw results, not adjusted for age, mileage, or peer mix. The MOT does not test engine or gearbox internals.
These are patterns across 2017 Toyota Prius vehicles in 2025, not a prediction that any one car will have them. Faults are grouped by part of the car. They come from MOT defect codes, not manufacturer bulletins, recalls or a diagnosis of any one car.
Suspension
Two faults. The strongest is the anti-roll bar linkage ball joint dust cover (front): 7.0 times as often as on similar cars.
Figures below are measured across the 1,363 of 1,364 failed first attempts (99.9%) that recorded an odometer reading in 2025. Mileage is needed to compare like with like.
We only list faults with at least 20 failures and a rate of about 2.0 times that of similar cars, which keeps one-off results out of the list.
Anti-roll bar linkage ball joint dust cover (front)
What it means
A suspension joint dust cover that is severely deteriorated is Minor. It becomes Major once it is missing or no longer prevents the ingress of dirt, so what matters is whether it still keeps dirt out. DVSA words this for any suspension joint dust cover, and files it here under anti-roll bars.
Anti-roll bar ball joint dust cover (front)
Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.
Lamps and electrical
One fault: rear fog light, 6.8 times as often as on similar cars.
Rear fog light
What it means
A missing obligatory rear fog lamp, one that is not working, or one that does not emit a steady red light is graded Major. A rear fog lamp adversely affected by the operation of any other lamp is Major too. The manual allows it to go out when main beam is switched on or when dipped beam headlamps are switched off.
Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.
Visibility
One fault: windscreen wipers (front), 3.0 times as often as on similar cars.
Windscreen wipers (front)
Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.
MOT pass rates
How first tests ended, and how the pass rates are counted.
- Passed first time
- 86in every 100
- Passed on the first test.
- Fixed at the station
- 5in every 100
- Failed, then fixed at the test station the same day.
- Failed
- 9in every 100
- Did not pass, and were not fixed at the test station.
First-attempt pass 86.5% of 10,100 first tests (2025): only cars that passed first time count. Official-style pass 91.1%: cars fixed at the test station also count as a pass. The 5 fixed and the 9 not fixed make the 14 in every 100 that did not pass first time.
Same model, other years
Passed first time in every 100, all tested in 2025.
Newer cars are younger, so look for a jump rather than the climb.
| Year | Passed first time | First tests |
|---|---|---|
| 2004 | 61 in every 100 | 718 |
| 2005 | 62 in every 100 | 1,997 |
| 2006 | 60 in every 100 | 3,011 |
| 2007 | 63 in every 100 | 5,787 |
| 2008 | 64 in every 100 | 5,840 |
| 2009 | 65 in every 100 | 6,052 |
| 2010 | 67 in every 100 | 8,502 |
| 2011 | 68 in every 100 | 6,402 |
| 2012 | 72 in every 100 | 7,189 |
| 2013 | 73 in every 100 | 7,387 |
| 2014 | 77 in every 100 | 8,789 |
| 2015 | 78 in every 100 | 8,452 |
| 2016 | 83 in every 100 | 9,674 |
| 2017 This car | 86 in every 100 | 10,100 |
| 2018 | 88 in every 100 | 10,102 |
| 2019 | 87 in every 100 | 11,080 |
| 2020 | 88 in every 100 | 7,409 |
| 2021 | 91 in every 100 | 2,167 |
| 2022 | 92 in every 100 | 1,166 |
If you are buying one
What this year's MOT record means for the decision in front of you.
Mileage makes a modest difference on a 2017 Prius.
Of 2017 Prius vehicles with under 54,000 miles, 90 in every 100 passed their 2025 MOT first time. With 164,000 miles or more, 83 in every 100 did.
What to check at your mileage
How often each fault turned up on a failed first test, by the car's mileage. Read it as: what is likely to need looking at on a car like the one in front of you.
| Under 54,000 | 81,000–114,000 | 164,000 and over | |
|---|---|---|---|
| Tyre tread depth (front) | 0.7 | 2.0 | 2.5 |
| Anti-roll bar linkage ball joint dust cover (front) | 0.6 | 2.2 | 1.4 |
| Windscreen wipers (front) | 1.6 | 1.4 | 1.1 |
| Tyre condition (front) | 1.1 | 1.1 | 0.7 |
| Brake pads (rear) | 0.4 | 1.3 | 0.7 |
Faults per 100 first tests, by the car's mileage at the test.
When a car fails
of failed cars had one item to fix.
of failed cars had three or more items to fix.
of all first tests had a defect the tester marked dangerous (unsafe to drive away).
Every figure here is a first-attempt MOT rate from DVSA open data for this model line, for cars of this model year tested in 2025. Each mileage band holds a fifth of the tests. MOTs do not test engine or gearbox internals, so this is a pre-purchase checklist, not a full reliability score.
FAQs
Short answers about how to read this model-year guide.
About this data
How this page is built and what it can (and can't) say.
These figures come from UK MOT open data for this model year. We surface common failure patterns against similar cars, not a full reliability score, and not a pass/fail verdict on any individual vehicle.
What we include
UK Class 4 cars only. Normal MOT tests (not retests); first test per vehicle per calendar year; results pass, PRS, or fail.
Same-day repairs
PRS means the car failed items that were fixed at the test station and then passed the same day. We count PRS as a first-attempt fail in headline rates so same-day repairs do not hide problems.
How we compare
We compare this model year with other Class 4 cars of similar age and mileage in the same test year. This model family is left out of the peer group so the car is not measured against itself.
What this does not cover
- MOTs do not cover engine internals, gearboxes, or many electronics; this is not a full reliability score.
- Common faults come from MOT defect stats, not manufacturer TSBs or recalls.
- Age and mileage matching reduces, but does not remove, differences in how cars were used and maintained.
- If the data for a car is too thin to say anything useful, we say so rather than guess.
Contains public sector information licensed under the Open Government Licence v3.0.
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