At a glance
How 5,634 first tests went in 2025.
- Passed first time
- 87 in every 100
- Did not pass first time
- 13 in every 100723 failed first-attempt tests
- The typical car
- 4 yearsabout 31,015 miles
- First tests counted
- 5,634
What failed most often
- Brake pads (rear)17 in every 100 failed tests
- Tyre condition (front)14 in every 100 failed tests
- Petrol engine warning light12 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 2021 Vauxhall Astra vehicles in 2025, not a prediction that any one car will have them. Faults are grouped by part of the car. A wear pattern follows age and use more than the way the car was built. They come from MOT defect codes, not manufacturer bulletins, recalls or a diagnosis of any one car.
Noise, emissions and leaks
One fault: petrol engine warning light, 7.9 times as often as on similar cars.
Figures below are measured across the 722 of 723 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.
Petrol engine warning light
What it means
The malfunction indicator lamp (MIL) on a petrol engine is a Major failure when it is illuminated indicating a malfunction. The detail line DVSA gives for the same row also names an inoperative lamp. The test covers only certain petrol vehicles, depending on their age, size and fuel type.
Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.
Lamps and electrical
Two faults. The strongest is the individual sidelight or tail light (rear): 4.5 times as often as on similar cars.
Individual sidelight or tail light (rear)
What it means
A position lamp showing red light to the front or white light to the rear is Major. Rear lamps must show a steady red light, and front ones can show white, predominantly white with a blue tinge, or yellow if combined in a yellow headlamp. With a multiple light source, up to half not working is Minor and more than half is Major.
Brake light (rear)
What it means
All stop lamps missing or not working is graded Dangerous, and so is a stop lamp that stays on when the brakes are released. A stop lamp that is missing or not working is Major. On some vehicles with LED rear lamps, part of the stop lamp can go out when the rear fog lamp is lit, which is not regarded as a defect.
Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.
Brakes
Two wear patterns. The strongest is the brake pads (rear): 3.6 times as often as on similar cars.
Brake pads (rear)
What it means
A pad worn down to its wear indicator, or contaminated with oil or grease, is Major. A pad worn below the set thickness limit, missing or incorrectly mounted is Dangerous. The manual treats an illuminated brake wear indicator as no reason for failure, although DVSA also lists an illuminated indicator as a Major row.
Also noted as an advisory
Testers also noted it as an advisory, worn but not yet failing, on 101 first tests, 2.5 times as often as on similar cars.
Brake pads (front)
What it means
A pad worn down to its wear indicator, or contaminated with oil or grease, is Major. A pad worn below the set thickness limit, missing or incorrectly mounted is Dangerous. The manual treats an illuminated brake wear indicator as no reason for failure, although DVSA also lists an illuminated indicator as a Major row.
Data: UK MOT open data, 2025. Compared with cars of the same age and mileage. Advisories count notes recorded on failed first tests only.
Tyres
One wear pattern: tyre pressure monitoring system, 2.3 times as often as on similar cars.
Tyre pressure monitoring system
What it means
A tyre pressure monitoring system that is obviously inoperative is graded Major, and so is one listed as malfunctioning or obviously inoperative. The Minor row uses the word malfunctioning too, but its detail is a warning lamp indicating a fault, and it also covers a tyre that is obviously under-inflated.
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
- 87in every 100
- Passed on the first test.
- Fixed at the station
- 3in every 100
- Failed, then fixed at the test station the same day.
- Failed
- 10in every 100
- Did not pass, and were not fixed at the test station.
First-attempt pass 87.2% of 5,634 first tests (2025): only cars that passed first time count. Official-style pass 89.9%: cars fixed at the test station also count as a pass. The 3 fixed and the 10 not fixed make the 13 in every 100 that did not pass first time.
Petrol and diesel
Figures are in every 100 first tests. Cars with more miles usually fail more often, so the same-mileage figure gives every fuel the mileage mix of all the cars in this year.
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 |
|---|---|---|
| 1997 | 59 in every 100 | 419 |
| 1998 | 61 in every 100 | 424 |
| 1999 | 56 in every 100 | 739 |
| 2000 | 56 in every 100 | 1,248 |
| 2001 | 57 in every 100 | 2,356 |
| 2002 | 55 in every 100 | 4,206 |
| 2003 | 57 in every 100 | 5,631 |
| 2004 | 56 in every 100 | 5,960 |
| 2005 | 53 in every 100 | 10,854 |
| 2006 | 51 in every 100 | 16,611 |
| 2007 | 53 in every 100 | 27,312 |
| 2008 | 55 in every 100 | 28,455 |
| 2009 | 55 in every 100 | 29,686 |
| 2010 | 59 in every 100 | 40,145 |
| 2011 | 61 in every 100 | 37,568 |
| 2012 | 64 in every 100 | 44,619 |
| 2013 | 65 in every 100 | 52,491 |
| 2014 | 66 in every 100 | 48,410 |
| 2015 | 67 in every 100 | 44,368 |
| 2016 | 73 in every 100 | 53,101 |
| 2017 | 78 in every 100 | 43,869 |
| 2018 | 80 in every 100 | 28,645 |
| 2019 | 83 in every 100 | 20,311 |
| 2020 | 83 in every 100 | 5,926 |
| 2021 This car | 87 in every 100 | 5,634 |
| 2022 | 89 in every 100 | 2,817 |
If you are buying one
What this year's MOT record means for the decision in front of you.
Mileage matters most on a 2021 Astra.
Of 2021 Astra vehicles with under 19,000 miles, 94 in every 100 passed their 2025 MOT first time. With 47,000 miles or more, 81 in every 100 did.
Petrol or diesel?
| Typical mileage | Passed first time, as tested | Passed first time, same mileage | |
|---|---|---|---|
| Petrol | 28,397 miles | 87 | 87 |
| Diesel | 45,114 miles | 86 | 89 |
Figures are in every 100 first tests. At the same mileage there is no clear difference between the two.
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 19,000 | 27,000–35,000 | 47,000 and over | |
|---|---|---|---|
| Brake pads (rear) | 0.2 | 3.3 | 2.7 |
| Tyre condition (front) | 2.0 | 1.1 | 1.7 |
| Petrol engine warning light | 0.6 | 1.2 | 2.8 |
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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