2020 MG ZS — MOT failures & pass rate
Across 42,223 MOT tests, the 2020 MG ZS recorded an 89.0% pass rate. Small SUVs of a similar age fail 7.9% of the time, so this is 3.1pp worse than the group it competes with. Failures cluster in tyres, lighting & signalling and brakes.
What the MOT record shows
No single area dominates — tyres (4.5%) and lighting & signalling (4.0%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are headlamp, tread depth and brake pads — headlamp alone was recorded 1,357 times.
Condition tracks the odometer closely. Failures run at 7.8% in the 0-30k band and 12.5% in the 150k+ band, a 4.7-point spread.
Split by fuel, petrol examples fail 3.5pp more often than electric ones (12.5% vs 9.0%) — worth weighing if you have a choice.
Advisories point at the next bill rather than this one: tyres was flagged on 22.8% of tests without failing them.
The trend is worsening — 1.9% of tests failed in 2021 against 13.5% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 4.5% | 1,893 |
| 2 | Lighting & signalling | 4.0% | 1,685 |
| 3 | Brakes | 3.5% | 1,477 |
| 4 | Visibility | 1.6% | 688 |
| 5 | Emissions & environmental | 1.3% | 534 |
| 6 | Suspension | 1.0% | 420 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Headlamp | 1,357 |
| 2 | Tread depth | 821 |
| 3 | Brake pads | 744 |
| 4 | Headlamp aim | 690 |
| 5 | Brake discs | 602 |
| 6 | Service brake performance | 501 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Tyres | 22.8% | 9,607 |
| 2 | Brakes | 19.1% | 8,071 |
| 3 | Other defects | 8.3% | 3,514 |
| 4 | Suspension | 4.7% | 1,976 |
| 5 | Visibility | 2.1% | 908 |
| 6 | Lighting & signalling | 1.2% | 498 |
Failure rate by mileage
Higher-mileage cars tend to fail more — often the most useful guide to real condition.
| Mileage band | Tests | Fail rate |
|---|---|---|
| 0-30k | 24,049 | 7.8% |
| 30-60k | 15,916 | 14.8% |
| 60-90k | 1,851 | 18.8% |
| 90-120k | 288 | 16.3% |
| 120-150k | 79 | 12.7% |
| 150k+ | 40 | 12.5% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Petrol | 23,467 | 12.5% |
| Electric | 18,756 | 9.0% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 206 | 1.9% |
| 2022 | 717 | 5.3% |
| 2023 | 13,431 | 8.5% |
| 2024 | 13,718 | 11.2% |
| 2025 | 14,151 | 13.5% |
What to check before buying a 2020 ZS
On a 2020 ZS, tyres is what the MOT record says goes wrong most — it appeared in 4.5% of tests. Check these areas before you commit.
- Tyres (4.5% of tests): Usually a quick, known-cost fix, but check tread, age and uneven wear (which can hint at alignment or suspension issues). Typical repair: £50–£120 per tyre.
- Lighting & signalling (4.0% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (3.5% of tests): Pads/discs are routine wear; binding, imbalance or corroded pipes are more serious — test for pulling under braking. Typical repair: £100–£350 per axle.
Repair costs are rough UK ballpark ranges to set expectations, not quotes — actual prices vary widely by car, parts and garage.
Frequently asked questions
How many 2020 MG ZSs pass their MOT?
89.0% of the 42,223 2020 MG ZS MOT tests in this dataset passed — a 11.0% fail rate.
What is the most common MOT failure on a 2020 MG ZS?
Tyres, recorded in 4.5% of tests, followed by lighting & signalling (4.0%).
Does the 2020 ZS get worse with mileage?
Its MOT fail rate rises from 7.8% in the 0-30k band to 12.5% in the 150k+ band.
Methodology & source. Based on 42,223 MOT tests. Dataset: DVSA MOT testing data (2021,2022,2023,2024,2025). Data last updated 2026-07-27. Figures reflect MOT-testable defects only — read the methodology for how these are calculated and what they don't measure.