2020 Mercedes-Benz Amg Cla 45 S 4Matic+ — MOT failures & pass rate
666 MOT tests on the 2020 Mercedes-Benz Amg Cla 45 S 4Matic+ are in this dataset, and 88.0% of them passed. All cars of a similar age fail 9.3% of the time, so this is 2.7pp worse than the group it competes with. Failures cluster in tyres, visibility and brakes.
What the MOT record shows
Tyres dominates the failure mix at 9.8% of all tests — 8.6 points clear of visibility, so it is the first thing to check.
At component level the recurring items are tread depth, registration plates and headlamp aim — tread depth alone was recorded 11 times.
A 60-90k example is materially riskier than a 0-30k one: 17.9% versus 11.6%.
Advisories point at the next bill rather than this one: tyres was flagged on 15.6% of tests without failing them.
The trend is improving — the fail rate fell from 13.8% in 2023 to 11.6% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 9.8% | 65 |
| 2 | Visibility | 1.2% | 8 |
| 3 | Brakes | 1.1% | 7 |
| 4 | Other defects | 0.9% | 6 |
| 5 | Emissions & environmental | 0.9% | 6 |
| 6 | Lighting & signalling | 0.8% | 5 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Tread depth | 11 |
| 2 | Registration plates | 10 |
| 3 | Headlamp aim | 7 |
| 4 | Washers | 4 |
| 5 | Wipers | 4 |
| 6 | Malfunction indicator lamp | 4 |
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 | 15.6% | 104 |
| 2 | Brakes | 6.8% | 45 |
| 3 | Other defects | 4.3% | 29 |
| 4 | Visibility | 2.9% | 19 |
| 5 | Lighting & signalling | 1.2% | 8 |
| 6 | Suspension | 0.4% | 3 |
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 | 355 | 11.6% |
| 30-60k | 269 | 11.9% |
| 60-90k | 39 | 17.9% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2023 | 225 | 13.8% |
| 2024 | 212 | 10.8% |
| 2025 | 216 | 11.6% |
What to check before buying a 2020 Amg Cla 45 S 4Matic+
On a 2020 Amg Cla 45 S 4Matic+, tyres is what the MOT record says goes wrong most — it appeared in 9.8% of tests. Check these areas before you commit.
- Tyres (9.8% 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.
- Visibility (1.2% of tests): Wipers, washers, mirrors and screen damage — usually inexpensive, but check for chips in the driver's line of sight. Typical repair: £15–£150.
- Brakes (1.1% 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.
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 Mercedes-Benz Amg Cla 45 S 4Matic+s pass their MOT?
88.0% of the 666 2020 Mercedes-Benz Amg Cla 45 S 4Matic+ MOT tests in this dataset passed — a 12.0% fail rate.
What is the most common MOT failure on a 2020 Mercedes-Benz Amg Cla 45 S 4Matic+?
Tyres, recorded in 9.8% of tests, followed by visibility (1.2%).
Does the 2020 Amg Cla 45 S 4Matic+ get worse with mileage?
Its MOT fail rate rises from 11.6% in the 0-30k band to 17.9% in the 60-90k band.
Methodology & source. Based on 666 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.