40,668 tests in 2025
MG Zs reliability and MOT pass rate
84.7% passed first time. The 15.3% fail rate is 7.3 points better than the all-car average, on a median example 4 years old with 30,980 miles.
Petrol, diesel and hybrid versions. The electric version has its own page: MG Zs Electric.
Pass rate
84.7%
22.6% of all cars failed; 15.3% of these did.
Fixed on the day
3.4%
Passed after a defect was put right during the visit.
Median at test
30,980 mi
4 years old.
Fail rate by age
| Age at test | Tests | Fail rate |
|---|---|---|
| 3-5 years | 26,380 | 12.4% |
| 6-9 years | 12,397 | 20.7% |
| 10-13 years | 0 | — |
| 14+ years | 998 | 33.7% |
What the Zs fails on
Share of failed tests with at least one fail item in each DVSA inspection section. A test can fail in several sections at once.
- Brakes1,419 dangerous39.1%
- Tyres1,681 dangerous31%
- Lamps, reflectors and electrical equipment12 dangerous19.2%
- Suspension31 dangerous18%
- Noise, emissions and leaks4 dangerous11.1%
- Visibility2 dangerous9.9%
- Body, chassis, structure15 dangerous3.4%
- Steering24 dangerous2.2%
Is the Zs getting worse?
The fail rate rose 1.5 points to 15.3% from 2022 to 2025, against a rising rate across all cars.
| Year | Tests | Median age | Fail rate | All cars | |
|---|---|---|---|---|---|
| 2022 | 15,179 | 3 | 13.8% | 22.5% | |
| 2023 | 21,853 | — | 14.6% | 22.8% | |
| 2024 | 26,627 | — | 14.9% | 23.2% | |
| 2025 | 40,508 | — | 15.3% | 22.6% |
Fail rate is first attempts at class 4 tests. Median age is the age of a typical Zs at its test that year, and it is the number to watch: across the whole fleet each extra year of age adds roughly 1.9 points to the fail rate, so a model whose age and fail rate rise together is simply getting older.
The exact defects that fail it
Every failure item DVSA recorded against a Zs in 2025, counted by how many tests each one appeared on.
- 1Brake pads: less than 1.5 mm thick938 tests
- 2Tread depth: tread depth below requirements of 1.6mm813 tests
- 3Headlamp: not working on dipped beam490 tests
- 4Condition: has a cut in excess of the requirements deep enough to reach the ply or cords455 tests
- 5Wipers: does not clear the windscreen effectively428 tests
- 6Rbt (sp): efficiency below requirements424 tests
- 7Brake discs: significantly and obviously worn421 tests
- 8Coil spring: fractured or broken389 tests
What wears out first
Advisories are the tester flagging wear that is still legal. A typical Zs collects 2.35 of them per test, and these are the ones that come up most. Treat it as the running-repairs list for the next year or two.
- 1Brake discs: in such a condition that it is seriously weakened7,038 tests
- 2Tread depth: tread depth below requirements of 1.6mm6,252 tests
- 3Brake pads: less than 1.5 mm thick3,958 tests
- 4Condition: has a tear, caused by separation or partial failure of its structure2,343 tests
- 5Non-component advisories: Child Seat fitted not allowing full inspection of adult belt1,663 tests
- 6Non-component advisories: Nail in tyre1,225 tests
- 7Service brake performance: excessively binding1,094 tests
- 8Brake discs: significantly and obviously worn873 tests
Questions
What is the MG Zs MOT pass rate?
84.7% of the 40,668 MG Zs first-attempt MOTs in 2025 passed. The fail rate of 15.3% compares with 22.6% across all cars. A further 3.4% passed after a defect was fixed during the test visit.
What does a MG Zs usually fail on?
The single most common failure is "Brake pads: less than 1.5 mm thick", recorded on 938 failed tests, followed by "Tread depth: tread depth below requirements of 1.6mm" and "Headlamp: not working on dipped beam". By section, brakes appears in 39.1% of failures, tyres appears in 31% of failures, lamps, reflectors and electrical equipment appears in 19.2% of failures.
Does age change the odds?
Sharply. At 3 to 5 years old the fail rate was 12.4%; at 14+ years it was 33.7%. The median MG Zs tested in 2025 was 4 years old with 30,980 miles.
Is the MG Zs getting less reliable?
The fail rate rose 1.5 points to 15.3% from 2022 to 2025, against a rising rate across all cars.
First-attempt class 4 tests, 2025, from DVSA’s anonymised MOT data (OGL v3, retrieved 2026-09-12). DVSA records newer cars trim by trim; this page adds every Zs trim together. Year-on-year figures come from the same DVSA extracts for 2026 and earlier years. Full method on the pass rates hub.
Other MG models
- Hs 8.5%
- 3 19.1%
- Zs Electric 12.5%
- 5 10.5%
Checking a particular Zs?
The odds above are the model. The car in front of you has its own record: every test, every advisory, the mileage at each one.
Due a test? Find an approved MOT station near you.