At a glance
How 4,845 first tests went in 2025.
- Passed first time
- 74 in every 100
- Did not pass first time
- 26 in every 1001,237 failed first-attempt tests
- The typical car
- 7 yearsabout 45,782 miles
- First tests counted
- 4,845
What failed most often
- Headlight9 in every 100 failed tests
- Coil spring (rear)9 in every 100 failed tests
- Tyre condition (front)9 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 2018 MG ZS 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.
Suspension
Two faults. The strongest is the wheel bearings (front): 20 times as often as on similar cars.
Figures below are measured across the 1,237 failed first attempts in 2025 that had a mileage recorded, which allows a like-for-like comparison.
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.
Wheel bearings (front)
Also noted as an advisory
Testers also noted it as an advisory, worn but not yet failing, on 42 first tests, 18 times as often as on similar cars.
Coil spring (rear)
What it means
A missing bump stop rubber is not a reason to fail a coil spring. When the vehicle is jacked and lowered, a spring that does not correctly locate as the suspension returns to its normal running position is rejected as insecurely attached. A missing spring is Major, and graded Dangerous where directional control is affected.
Data: UK MOT open data, 2025. Compared with cars of the same age and mileage. Advisories count notes recorded on failed first tests only.
Brakes
Five faults and one wear pattern. The strongest is the anti-lock braking system (ABS): 14 times as often as on similar cars.
Anti-lock braking system (ABS)
What it means
ABS is failed as removed only where it has obviously been removed, because not every vehicle in the age range where removal is not permitted has ABS. A warning lamp that does not light or shows an ABS fault is Major, as is a missing or excessively damaged wheel speed sensor. Every failure row for this component is Major.
Electronic stability control
What it means
An ESC warning lamp is failed only when the tester is certain it indicates an ESC malfunction, because the lamp takes various forms and the owner's handbook may need checking. The system is also called ESP, VDC or DSC, among many other names. Every failure row is Major, covering the lamp, wheel speed sensors, wiring, other components and the switch.
Handbrake lever
Brake discs (rear)
What it means
A brake disc or drum must be significantly worn before it is rejected, and being worn below the manufacturer's recommended limits is not a reason in itself. Significantly and obviously worn is Major, as is contamination with oil or grease. A disc or drum that is fractured, insecure, seriously weakened or missing is graded Dangerous.
Also noted as an advisory
Testers also noted it as an advisory, worn but not yet failing, on 276 first tests, 3.0 times as often as on similar cars.
Handbrake efficiency below minimum (roller test)
What it means
A parking brake with efficiency below the minimum requirement is Major, and graded Dangerous where efficiency is less than half of the required value. On a roller brake tester, the requirement counts as met if more than half of the wheels of a brake system lock. The check applies only to vehicles whose parking brake was not already tested as the secondary brake.
Brake performance (roller test, rear)
Also noted as an advisory
Testers also noted it as an advisory, worn but not yet failing, on 60 first tests, 4.5 times as often as on similar cars.
Data: UK MOT open data, 2025. Compared with cars of the same age and mileage. Advisories count notes recorded on failed first tests only.
Lamps and electrical
One fault: headlight (front), 3.6 times as often as on similar cars.
Headlight (front)
What it means
On vehicles first used on or after a set date, a halogen headlamp unit converted to take HID or LED bulbs fails for light source and lamp not compatible, which is Major. A complete unit built with those light sources is not failed for that. The precise position of the lamps is not part of the inspection beyond a visual look to see that they sit at about the same height and distance from each side.
Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.
Tyres
One wear pattern: tyre pressure monitoring system, 2.0 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.
Noise, emissions and leaks
One fault: petrol engine warning light, 2.0 times as often as on similar cars.
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.
Advisories
Other things testers noted as worn or close to failing, more often than on similar cars.
An advisory is a note from the tester about something that has not failed yet. It is an early warning, not a fail. Advisories for the faults above are shown with those faults.
Suspension arm (front)
Suspension sub-frame (front)
Engine oil leaks
Data: UK MOT open data, 2025. Counts cover advisories recorded on failed first tests only, 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
- 74in 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
- 21in every 100
- Did not pass, and were not fixed at the test station.
First-attempt pass 74.5% of 4,845 first tests (2025): only cars that passed first time count. Official-style pass 78.8%: cars fixed at the test station also count as a pass. The 5 fixed and the 21 not fixed make the 26 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. A year earlier (2024), when these cars were a year younger, 76 in every 100 passed first time.
| Year | Passed first time | First tests |
|---|---|---|
| 2017 | 66 in every 100 | 333 |
| 2018 This car | 74 in every 100 | 4,845 |
| 2019 | 75 in every 100 | 8,181 |
| 2020 | 81 in every 100 | 11,763 |
| 2021 | 86 in every 100 | 14,459 |
| 2022 | 85 in every 100 | 17,287 |
If you are buying one
What this year's MOT record means for the decision in front of you.
Mileage matters most on a 2018 MG ZS.
Of 2018 MG ZS vehicles with under 31,000 miles, 87 in every 100 passed their 2025 MOT first time. With 63,000 miles or more, 64 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 31,000 | 41,000–51,000 | 63,000 and over | |
|---|---|---|---|
| Headlight | 0.5 | 2.8 | 3.0 |
| Coil spring (rear) | 0.8 | 2.1 | 3.5 |
| Tyre condition (front) | 1.3 | 1.9 | 4.0 |
| Handbrake efficiency below minimum (roller test) | 0.2 | 1.9 | 4.5 |
| Tyre tread depth (front) | 0.5 | 1.8 | 3.8 |
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.
Check any vehicle’s MOT history
Full MOT history, mileage records, and reliability insights for any UK vehicle.
Run a free check