Mercedes-Benz Amg Cla 45 S 4Matic+ MOT pass rate & common failures
Across 5 model years and 1,329 tests, the Mercedes-Benz Amg Cla 45 S 4Matic+ passes its MOT 87.2% of the time. That is 3.8 percentage points worse than all cars of a similar age, which fail at 8.9%. Its most common failure areas are tyres, lighting & signalling and emissions & environmental.
What the MOT record shows
Tyres dominates the failure mix at 9.7% of all tests — 8.5 points clear of lighting & signalling, so it is the first thing to check.
At component level the recurring items are registration plates, headlamp aim and tread depth — registration plates alone was recorded 23 times.
Condition tracks the odometer closely. Failures run at 12.6% in the 0-30k band and 18.6% in the 60-90k band, a 5.9-point spread.
Advisories point at the next bill rather than this one: tyres was flagged on 14.8% of tests without failing them.
How it compares
By model year
Every Amg Cla 45 S 4Matic+ model year with a usable sample. Years with their own detailed report are linked.
| Year | Tests | Pass rate | Fail rate | Most common failure |
|---|---|---|---|---|
| 2019 | 44 | 81.8% | 18.2% | Tyres |
| 2020 | 666 | 88.0% | 12.0% | Tyres |
| 2021 | 464 | 87.5% | 12.5% | Tyres |
| 2022 | 141 | 83.7% | 16.3% | Tyres |
Most common failures (all years)
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 9.7% | 129 |
| 2 | Lighting & signalling | 1.2% | 16 |
| 3 | Emissions & environmental | 1.1% | 14 |
| 4 | Other defects | 1.1% | 14 |
| 5 | Visibility | 1.1% | 14 |
| 6 | Brakes | 0.9% | 12 |
| 7 | Suspension | 0.6% | 8 |
| 8 | Road wheels | 0.5% | 7 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Registration plates | 23 |
| 2 | Headlamp aim | 23 |
| 3 | Tread depth | 19 |
| 4 | Catalyst emissions | 10 |
| 5 | Wipers | 8 |
| 6 | Washers | 6 |
| 7 | Brake pads | 5 |
| 8 | Malfunction indicator lamp | 5 |
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 | 14.8% | 197 |
| 2 | Brakes | 5.6% | 75 |
| 3 | Other defects | 4.5% | 60 |
| 4 | Visibility | 3.1% | 41 |
| 5 | Suspension | 0.7% | 9 |
| 6 | Lighting & signalling | 0.6% | 8 |
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 | 776 | 12.6% |
| 30-60k | 479 | 12.3% |
| 60-90k | 70 | 18.6% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2023 | 249 | 14.1% |
| 2024 | 449 | 10.9% |
| 2025 | 612 | 13.7% |
What to check before buying a Mercedes-Benz Amg Cla 45 S 4Matic+
- Tyres (9.7% 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 (1.2% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Emissions & environmental (1.1% of tests): More common on older diesels (DPF/EGR) — can be expensive; check for warning lights and smoke. Typical repair: £100–£600.
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 Mercedes-Benz Amg Cla 45 S 4Matic+?
87.2% of the 1,329 Mercedes-Benz Amg Cla 45 S 4Matic+ MOT tests in this dataset passed, a 12.8% fail rate, across model years 2019–2023.
What does the Mercedes-Benz Amg Cla 45 S 4Matic+ most often fail its MOT on?
Tyres, recorded in 9.7% of tests, then lighting & signalling (1.2%).
How much does mileage affect Amg Cla 45 S 4Matic+ MOT results?
Fail rates run at 12.6% for cars in the 0-30k band and 18.6% for 60-90k, a 5.9-point difference.
Methodology & source. Based on 1,329 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.