MG ZR MOT pass rate & common failures
The MG ZR appears in 15,350 MOT tests spanning model years 1994–2021, and 74.8% of them passed. Against small family cars of a similar age (28.0% fail rate), the ZR comes out 2.8pp better. Its most common failure areas are lighting & signalling, body, structure & corrosion and brakes.
What the MOT record shows
One area stands out: lighting & signalling, recorded in 15.0% of tests against 9.8% for the next-worst category.
At component level the recurring items are headlamp aim, joints and catalyst emissions — headlamp aim alone was recorded 1,021 times.
A 150k+ example is materially riskier than a 0-30k one: 30.2% versus 14.6%.
Fuel type barely separates them — diesel fails 24.6% of the time against 25.2% for petrol.
Tyres is the most common advisory, noted on 23.3% of tests — work that passed today but is likely due soon.
The trend is improving — the fail rate fell from 26.7% in 2021 to 22.8% in 2025, as the worst-kept examples leave the fleet.
How it compares
By model year
Every ZR model year with a usable sample. Years with their own detailed report are linked.
| Year | Tests | Pass rate | Fail rate | Most common failure |
|---|---|---|---|---|
| 2001 | 554 | 74.2% | 25.8% | Lighting & signalling |
| 2002 | 1,978 | 74.1% | 25.9% | Lighting & signalling |
| 2003 | 3,935 | 74.7% | 25.3% | Lighting & signalling |
| 2004 | 5,157 | 75.0% | 25.1% | Lighting & signalling |
| 2005 | 3,217 | 75.7% | 24.3% | Lighting & signalling |
| 2006 | 450 | 74.0% | 26.0% | Lighting & signalling |
| 2007 | 30 | 63.3% | 36.7% | Brakes |
Most common failures (all years)
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 15.0% | 2,307 |
| 2 | Body, structure & corrosion | 9.8% | 1,508 |
| 3 | Brakes | 8.8% | 1,348 |
| 4 | Suspension | 6.8% | 1,037 |
| 5 | Emissions & environmental | 6.6% | 1,011 |
| 6 | Visibility | 4.6% | 707 |
| 7 | Tyres | 4.5% | 694 |
| 8 | Steering | 3.0% | 457 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Headlamp aim | 1,021 |
| 2 | Joints | 974 |
| 3 | Catalyst emissions | 915 |
| 4 | Component mounting prescribed areas | 907 |
| 5 | Service brake performance | 681 |
| 6 | Position lamp | 621 |
| 7 | Headlamp | 565 |
| 8 | Wipers | 527 |
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 | 23.3% | 3,582 |
| 2 | Brakes | 22.6% | 3,475 |
| 3 | Suspension | 21.0% | 3,220 |
| 4 | Body, structure & corrosion | 19.4% | 2,985 |
| 5 | Lighting & signalling | 13.6% | 2,080 |
| 6 | Emissions & environmental | 11.8% | 1,812 |
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 | 685 | 14.6% |
| 30-60k | 3,275 | 21.6% |
| 60-90k | 5,300 | 25.7% |
| 90-120k | 3,947 | 27.3% |
| 120-150k | 1,494 | 28.2% |
| 150k+ | 620 | 30.2% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Petrol | 13,931 | 25.2% |
| Diesel | 1,419 | 24.6% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 4,341 | 26.7% |
| 2022 | 3,516 | 25.2% |
| 2023 | 2,974 | 25.2% |
| 2024 | 2,443 | 24.3% |
| 2025 | 2,076 | 22.8% |
What to check before buying a MG ZR
- Lighting & signalling (15.0% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Body, structure & corrosion (9.8% 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+.
- Brakes (8.8% 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
What is the MOT pass rate for the MG ZR?
74.8% of the 15,350 MG ZR MOT tests in this dataset passed, a 25.2% fail rate, across model years 1994–2021.
What does the MG ZR most often fail its MOT on?
Lighting & signalling, recorded in 15.0% of tests, then body, structure & corrosion (9.8%).
How much does mileage affect ZR MOT results?
Fail rates run at 14.6% for cars in the 0-30k band and 30.2% for 150k+, a 15.6-point difference.
Is the diesel or petrol ZR more reliable at MOT time?
On MOT-testable defects the diesel fails 24.6% of the time against 25.2% for the petrol. This covers testable items only, not engine or gearbox reliability.
Methodology & source. Based on 15,350 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.