2004 MG ZS — MOT failures & pass rate
Across 2,771 MOT tests, the 2004 MG ZS recorded a 73.2% pass rate. Small SUVs of a similar age fail 28.2% of the time, so this is 1.3pp better than the group it competes with. Failures cluster in lighting & signalling, brakes and body, structure & corrosion.
What the MOT record shows
No single area dominates — lighting & signalling (13.4%) and brakes (12.1%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are component mounting prescribed areas, headlamp aim and joints — component mounting prescribed areas alone was recorded 227 times.
A 150k+ example is materially riskier than a 0-30k one: 32.5% versus 17.1%.
Advisories point at the next bill rather than this one: brakes was flagged on 31.4% of tests without failing them.
The trend is improving — the fail rate fell from 29.3% in 2021 to 27.7% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 13.4% | 371 |
| 2 | Brakes | 12.1% | 335 |
| 3 | Body, structure & corrosion | 11.2% | 309 |
| 4 | Suspension | 10.5% | 292 |
| 5 | Emissions & environmental | 5.6% | 154 |
| 6 | Visibility | 4.5% | 125 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Component mounting prescribed areas | 227 |
| 2 | Headlamp aim | 198 |
| 3 | Joints | 163 |
| 4 | Service brake performance | 146 |
| 5 | Rbt (sp) | 129 |
| 6 | Catalyst emissions | 100 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Brakes | 31.4% | 870 |
| 2 | Suspension | 29.2% | 808 |
| 3 | Tyres | 21.5% | 595 |
| 4 | Body, structure & corrosion | 21.3% | 591 |
| 5 | Emissions & environmental | 11.0% | 304 |
| 6 | Lighting & signalling | 10.8% | 298 |
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 | 70 | 17.1% |
| 30-60k | 483 | 23.2% |
| 60-90k | 1,006 | 26.9% |
| 90-120k | 752 | 27.8% |
| 120-150k | 301 | 29.2% |
| 150k+ | 157 | 32.5% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Petrol | 2,554 | 26.7% |
| Diesel | 217 | 29.0% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 779 | 29.3% |
| 2022 | 647 | 25.5% |
| 2023 | 531 | 26.0% |
| 2024 | 438 | 24.9% |
| 2025 | 376 | 27.7% |
What to check before buying a 2004 ZS
On a 2004 ZS, lighting & signalling is what the MOT record says goes wrong most — it appeared in 13.4% of tests. Check these areas before you commit.
- Lighting & signalling (13.4% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (12.1% 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.
- Body, structure & corrosion (11.2% of tests): The one to take seriously on older cars — corrosion to structural areas can be costly and is an MOT failure. Typical repair: £200–£1,500+.
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 2004 MG ZSs pass their MOT?
73.2% of the 2,771 2004 MG ZS MOT tests in this dataset passed — a 26.9% fail rate.
What is the most common MOT failure on a 2004 MG ZS?
Lighting & signalling, recorded in 13.4% of tests, followed by brakes (12.1%).
Does the 2004 ZS get worse with mileage?
Its MOT fail rate rises from 17.1% in the 0-30k band to 32.5% in the 150k+ band.
Methodology & source. Based on 2,771 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.