Pass rate
93.9%
Above average — 2.7 pts ahead of the 91.2% that cars this age and mileage manage.
Across 395 recorded tests.
Typical repair bill £29–£71
2021 Mercedes-Benz Slc MOT pass rate
- 2021
- 3 trims combined
- typical 14,839 mi
Most common fault
Tyres
59.6% of faults · 19.8% nationally
mostly tread below the limit, cuts and sidewall bulges.
Part only £55–£85 for Tyre has a tear. What fitting it takes →
1.7 pts up across model years — 2.1% in 2016, 3.8% in 2020.
Which year to buy
- Best 2021 93.9% pass · this year
- Avoid 2016 87.5% pass
Across the 6 years on record, a spread of 6.4 points. See every year →
- First-attempt pass
- 93.5%
- Typical mileage
- 15k mi
The 2021 Mercedes-Benz Slc MOT pass rate is 93.9% of its MOT tests — 2.7 points ahead of what its age and mileage predict. Tyres is the biggest single reason it fails, at 59.6% of what testers record.
Check your postcode
MOT pass rates are national — type your postcode to see how Mercedes-Benz Slc does in your corner of the country.
Expert verdict
Tyres: 3.0× the national share
Tyres make up 59.6% of everything recorded on the 2021 Mercedes-Benz Slc, against 19.8% nationally — 39.8 points above. Check all four tyres yourself, including the inner shoulders, and look at the date stamp — a tyre can pass on tread and still be six years old.
- When it fails, it costs. Only 25% of this model’s typical repairs come in under £30 in parts — the failures here tend to be the kind that need a garage rather than a bulb.
- Based on a small sample. 395 tests back this page. That is enough to publish and to index, not enough to treat the decimal places as precise — read the pattern, not the second digit.
Written from this page's own figures: fault shares against the national composition, the like-for-like pass rate, and the priced repair list. How these are worked out
Watching a Mercedes-Benz Slc? Get an email when these numbers change .
Every Mercedes-Benz Slc first registered in 2021 is combined here — 3 trim and body variants in total — so the sample is as large as the DVSA data allows.
How does the 2021 Mercedes-Benz Slc compare?
Cars of this age and mileage average 91.2%, so this figure is 2.7 points ahead of what its age and mileage predict. On a first attempt, before any retests, the figure drops to 93.5%. The median 2021 Mercedes-Benz Slc in this dataset had covered 14,839 mi.
Pass rates also shift with the test month: tests recorded October–March passed 93.7% of the time, April–September 94.4%.
The single most recorded failure item is "Has a cut in excess of the requirements deep enough to reach the ply or cords", noted on 1.27% of tests.
- 395 recorded tests behind this page.
- 93.9% overall pass rate, 93.5% on a first attempt.
- Across every year of the Mercedes-Benz Slc, the average is 89.1% — best year 2021 (93.9%), worst 2016 (87.5%).
Figures count every completed test on this vehicle-year in the dataset, including retests. See methodology for the exact definition.
This page's data
- Tests analysed
- 395
- Typical mileage (median)
- 14,839 mi
- Make and model
- Mercedes-Benz Slc
- Updated
- 2026-11-05
Source: DVSA anonymised MOT test data (2023–2025), OGL v3.0.
Top part to budget for
Tyres
Usually a DIY or independent-garage job.
Does mileage affect the Slc MOT pass rate?
Pass rate by odometer reading. Bar lengths start at 84% so small gaps stay visible.
Regional pass rates for the Slc
| Region | Tests | Pass rate |
|---|---|---|
| South East | 86 | 94.2% |
| South West | 72 | 90.3% |
| North West | 43 | 93.0% |
| East of England | 41 | 97.6% |
| Scotland | 33 | 87.9% |
| Yorkshire | 33 | 93.9% |
| East Midlands | 29 | 100.0% |
| West Midlands | 19 | 94.7% |
| Wales | 15 | 93.3% |
Regions come from the postcode area recorded at the test station. Areas on region borders are assigned to the region with the majority of their population.
What fails a 2021 Slc
Everything a tester recorded on this vehicle, grouped into the inspection sections that produced it. The notch on each bar is the national share, so you can see at a glance whether this car is unusual or just ordinary.
A test can record several items, so these percentages do not add up to 100%. The exact strings, with prices, are in the full DVSA record at the bottom of this page.
Before your test
Three checks worth doing on a 2021 Slc
These are not generic tips — they are the faults recorded most often on this exact model, rewritten as things you can check yourself. All three take about ten minutes and cost nothing.
-
Check the wipers and washers 1.3% of tests
“wipers blade defective”
Run the wipers with the screen wet: they should clear it in one sweep without smearing or juddering. Top the washer bottle up and check both jets hit the screen.
-
Check the lights 0.8% of tests
“headlamp aim too high”
Switch everything on and walk round the car: both headlamps on dip and main, every indicator, both brake lights, reverse, fog and the two number-plate lamps. A bulb is a few pounds and a five-minute job.
-
Check the suspension joints 0.5% of tests
“ball joint dust cover severely deteriorated”
With the car parked on level ground, rock the top of each front wheel in and out while someone watches the suspension arm. Clunks, or rubber boots split and greasy, are what testers record here.
Shares are the proportion of tests on this vehicle that recorded the item, so they overlap: one test can record several.
What it costs to get a 2021 Slc through its MOT
Across the 10 items that are recorded most often on this model, the average repair comes to £29–£71 — and 25% of those repairs are parts that cost under £30.
- Average repair across the 10 common items
- £29–£71
- Cheapest common item: anti-lock braking system warning lamp…
- £3–£15
- Dearest common item: catalyst emissions lambda reading after 2nd…
- £60–£250
- Common items a careful owner can do at home
- 80%
- Repairs that still cost under £30
- 25%
Estimates from typical UK parts prices, weighted by how often each item appears in 395 MOT tests on this vehicle. They exclude diagnostics, retest fees and garage labour where the part is a DIY fit, and they are not figures from the DVSA dataset. Older and higher-mileage examples cost more than the average. How these estimates are built → · All MOT repair costs → · Cheapest cars to put through a test →
Every year of the Slc, side by side
6 model years on record, from 2016 to 2021. Across them the pass rate runs from 87.5% to 93.9% — a spread of 6.4 points. The bar under each year is the item that failed it most often.
- 2016 87.5% coil spring fractured or broken
- 2017 87.6% has a cut in excess of the…
- 2018 91.2% has a cut in excess of the…
- 2019 92.8% has a cut in excess of the…
- 2020 92.9% has a cut in excess of the…
- 2021 93.9%has a cut in excess of the…
Colour is the pass rate on a fixed scale, so a block means the same thing on any model. Each year links to its own page with the full fault breakdown.
Compare the 2021 Mercedes-Benz Slc with another year
The raw pass rate mostly measures age. The year comparison adds the like-for-like figure, the mileage bands and the repair bill.
Other 2021 cars with a similar record
- Citroen C1 93.9%
- Land Rover Defender 93.9%
- Hyundai Tucson N 93.9%
- Toyota Aygo 94.0%
- Jaguar I-Pace 94.0%
- Toyota Corolla Gr 94.0%
Closest pass rates among 2021 cars with at least 2,000 tests, so a small sample cannot flatter itself into the list. See the full rankings: best and worst MOT pass rates.
The full DVSA record for the 2021 Mercedes-Benz Slc 10 failure items · 6 advisories · 10 inspection categories · mileage brackets · all of it in the page, none of it above the fold
Every inspection category
Shares of the 155 individual items recorded on this vehicle, and the same share across all cars nationally. A single test can record several items, so a row is not a percentage of tests.
| Category | Items | This car | Nationally | Difference |
|---|---|---|---|---|
| Tyres | 93 | 59.60% | 19.76% | +39.84 |
| Non-component advisories | 12 | 7.70% | 4.18% | +3.52 |
| Suspension | 11 | 7.10% | 20.98% | −13.88 |
| Brakes | 11 | 7.10% | 20.89% | −13.79 |
| Lamps, reflectors and electrical equipment | 8 | 5.10% | 12.21% | −7.11 |
| Visibility | 8 | 5.10% | 4.97% | +0.13 |
| Road Wheels | 5 | 3.20% | 0.75% | +2.45 |
| Identification of the vehicle | 3 | 1.90% | 1.76% | +0.14 |
| Body, chassis, structure | 2 | 1.30% | 5.57% | −4.27 |
| Noise, emissions and leaks | 2 | 1.30% | 5.52% | −4.22 |
The exact failure items, in the tester's words
| Recorded item | Severity | Tests | Est. cost |
|---|---|---|---|
| Has a cut in excess of the requirements deep enough to reach the ply or cords Tyres | Major | 1.3% | £45–95 |
| Has ply or cords exposed Tyres | Major | 1.3% | £45–95 |
| Wipers blade defective Visibility | Minor | 1.3% | £8–22 |
| Headlamp aim too high Lamps, reflectors and electrical equipment | Rectified | 0.76% | £30–80 |
| Anti-lock braking system warning lamp indicates an ABS fault Brakes | Major | 0.51% | £3–15 |
| Ball joint dust cover severely deteriorated Suspension | Minor | 0.51% | £18–45 |
| Ball joint excessively worn Suspension | Major | 0.51% | £18–45 |
| Has a tear, caused by separation or partial failure of its structure Tyres | Major | 0.51% | £45–95 |
| Ball joint dust cover no longer prevents the ingress of dirt Suspension | Major | 0.25% | £18–45 |
| Catalyst emissions Lambda reading after 2nd fast idle outside specified limits Noise, emissions and leaks | Major | 0.25% | £60–250 |
Severity is as recorded: Major and Dangerous fail the test outright; Minor and Advisory do not. Costs are estimates from typical UK parts prices — see how they are built.
What testers noted without failing the car
Advisories are the early warnings — the same parts a year or two before they fail. Reading them is how you tell a car that has been maintained from one that has been patched.
| Recorded item | Severity | Tests | Est. cost |
|---|---|---|---|
| Has a tear, caused by separation or partial failure of its structure Tyres | Advisory | 7.8% | £45–95 |
| Tread depth below requirements of 1.6mm Tyres | Advisory | 6.3% | £45–95 |
| Has a cut in excess of the requirements deep enough to reach the ply or cords Tyres | Advisory | 2.0% | £45–95 |
| Tread depth tread pattern not visible over the whole tread area when minimum depth required is 1.0mm Tyres | Advisory | 1.8% | £45–95 |
| Has a bulge, caused by separation or partial failure of its structure Tyres | Advisory | 1.5% | £45–95 |
| Non-component advisories Nail in tyre Non-component advisories | Advisory | 1.5% | £45–95 |
Pass rate by mileage
| Mileage | Tests | Pass rate | Median odometer |
|---|---|---|---|
| 0-30k | 343 | 94.2% | 14,309 mi |
| 30-60k | 51 | 92.2% | 39,265 mi |
| 60-90k | 1 | 100.0% | 67,584 mi |
Source: 395 recorded tests on this vehicle-year. Every row above is recomputed from the same DVSA extract as the rest of the page — see the methodology.
2021 Slc MOT questions
What is the MOT pass rate for a 2021 Mercedes-Benz Slc?
93.9% of the 395 2021 Mercedes-Benz Slc tests in this dataset passed, against a national average of 91.2% for cars first used in 2021. First-attempt pass rate: 93.5%.
What are the most common MOT failures on a 2021 Mercedes-Benz Slc?
The three most recorded items are has a cut in excess of the requirements deep enough to reach the ply or cords (1.27%), has ply or cords exposed (1.27%), wipers blade defective (1.27%). Percentages are the share of tests on this vehicle that recorded the item.
Does mileage affect the 2021 Mercedes-Benz Slc MOT pass rate?
Yes. Cars under 30,000 miles passed 94.2% of the time, falling to 100.0% for those over 120,000 miles. The median 2021 Mercedes-Benz Slc in this dataset had covered 14,839 mi.
Does the season affect the 2021 Mercedes-Benz Slc MOT pass rate?
Tests recorded in the winter months (October–March) passed 93.7% of the time; summer months (April–September) passed 94.4%. Brakes, tyres and lights are tested harder in bad weather, but the difference is small on most models.