2004 Ford Mustang — MOT failures & pass rate
367 MOT tests on the 2004 Ford Mustang are in this dataset, and 82.3% of them passed. Against coupes & convertibles of a similar age (22.4% fail rate), the 2004 Mustang comes out 4.7pp better. Failures cluster in lighting & signalling, brakes and suspension.
What the MOT record shows
No single area dominates — lighting & signalling (9.8%) and brakes (9.8%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are rbt (sp), service brake performance and side repeaters — rbt (sp) alone was recorded 27 times.
Mileage is the strongest signal on the record: 14.0% of 0-30k cars fail, rising to 32.4% once past 120-150k — 2.3× the risk.
Brakes is the most common advisory, noted on 19.1% of tests — work that passed today but is likely due soon.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 9.8% | 36 |
| 2 | Brakes | 9.8% | 36 |
| 3 | Suspension | 4.4% | 16 |
| 4 | Emissions & environmental | 3.0% | 11 |
| 5 | Steering | 2.7% | 10 |
| 6 | Visibility | 2.5% | 9 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Rbt (sp) | 27 |
| 2 | Service brake performance | 20 |
| 3 | Side repeaters | 13 |
| 4 | Headlamp aim | 12 |
| 5 | Rear fog lamp | 11 |
| 6 | Registration plates | 10 |
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 | 19.1% | 70 |
| 2 | Suspension | 14.7% | 54 |
| 3 | Tyres | 10.6% | 39 |
| 4 | Other defects | 9.5% | 35 |
| 5 | Lighting & signalling | 9.3% | 34 |
| 6 | Emissions & environmental | 6.0% | 22 |
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 | 43 | 14.0% |
| 30-60k | 150 | 14.0% |
| 60-90k | 81 | 14.8% |
| 90-120k | 47 | 23.4% |
| 120-150k | 37 | 32.4% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 82 | 18.3% |
| 2022 | 79 | 17.7% |
| 2023 | 76 | 14.5% |
| 2024 | 63 | 19.1% |
| 2025 | 67 | 19.4% |
What to check before buying a 2004 Mustang
The failure pattern for this year is specific enough to inspect against: lighting & signalling accounted for 9.8% of tests. Start there.
- Lighting & signalling (9.8% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (9.8% 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.
- Suspension (4.4% of tests): Worn drop links, bushes, springs or shocks — listen for knocks over bumps and check for uneven tyre wear. Typical repair: £150–£450 per corner.
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 Ford Mustangs pass their MOT?
82.3% of the 367 2004 Ford Mustang MOT tests in this dataset passed — a 17.7% fail rate.
What is the most common MOT failure on a 2004 Ford Mustang?
Lighting & signalling, recorded in 9.8% of tests, followed by brakes (9.8%).
Does the 2004 Mustang get worse with mileage?
Its MOT fail rate rises from 14.0% in the 0-30k band to 32.4% in the 120-150k band.
Methodology & source. Based on 367 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.