Pass rate
88.5%
Above average — 2.7 pts behind the 91.2% that cars this age and mileage manage.
Across 78 recorded tests.
Typical repair bill £42–£102
2021 Mercedes-Benz Sl MOT pass rate
- 2021
- 3 trims combined
- typical 17,104 mi
Only 78 tests of this exact model and year are in the DVSA data, below the 100 we ask for before a page goes in the index. The figures are still shown, because they are the only ones there are.
Most common fault
Tyres
56.7% of faults · 19.8% nationally
mostly tread below the limit, cuts and sidewall bulges.
Which year to buy
- Best 2020 93.7% pass
- Avoid 2010 84.9% pass
Across the 22 years on record, a spread of 8.8 points. See every year →
- First-attempt pass
- 88.7%
- Typical mileage
- 17k mi
The 2021 Mercedes-Benz Sl MOT pass rate is 88.5% of its MOT tests — 2.7 points behind what its age and mileage predict. Tyres is the biggest single reason it fails, at 56.7% of what testers record.
Check your postcode
MOT pass rates are national — type your postcode to see how Mercedes-Benz Sl does in your corner of the country.
Expert verdict
Tyres: 2.9× the national share
Tyres make up 56.7% of everything recorded on the 2021 Mercedes-Benz Sl, against 19.8% nationally — 36.9 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 0% 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. 78 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 Sl? Get an email when these numbers change .
Every Mercedes-Benz Sl 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 Sl compare?
Cars of this age and mileage average 91.2%, so this figure is 2.7 points behind what its age and mileage predict. On a first attempt, before any retests, the figure drops to 88.7%. The median 2021 Mercedes-Benz Sl in this dataset had covered 17,104 mi.
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 5.13% of tests.
- 78 recorded tests behind this page.
- 88.5% overall pass rate, 88.7% on a first attempt.
- Across every year of the Mercedes-Benz Sl, the average is 87.2% — best year 2020 (93.7%), worst 2010 (84.9%).
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
- 78
- Typical mileage (median)
- 17,104 mi
- Make and model
- Mercedes-Benz Sl
- 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 Sl MOT pass rate?
Pass rate by odometer reading. Bar lengths start at 0% so small gaps stay visible.
Regional pass rates for the Sl
| Region | Tests | Pass rate |
|---|---|---|
| South East | 17 | 94.1% |
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 Sl
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 Sl
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 lights 2.6% of tests
“headlamp aim too low”
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 1.3% of tests
“ball joint excessively worn”
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.
-
Check the brake pipes 1.3% of tests
“rigid brake pipes excessively corroded”
Brake pipes run under the car, usually in front of the rear wheels. Flaking or crusty metal is what fails; a light dusting of surface rust does not. Worth asking a garage to look while it is on a ramp.
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 Sl through its MOT
Across the 8 items that are recorded most often on this model, the average repair comes to £42–£102 — and 0% of those repairs are parts that cost under £30.
- Average repair across the 8 common items
- £42–£102
- Cheapest common item: ball joint excessively worn
- £18–£45
- Dearest common item: steering box has excessive free play detected…
- £60–£200
- Common items a careful owner can do at home
- 50%
- Repairs that still cost under £30
- 0%
Estimates from typical UK parts prices, weighted by how often each item appears in 78 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 Sl, side by side
22 model years on record, from 2000 to 2021. Across them the pass rate runs from 84.9% to 93.7% — a spread of 8.8 points. The bar under each year is the item that failed it most often.
- 2000 86.5% ball joint dust cover severely…
- 2001 87.4% ball joint dust cover severely…
- 2002 85.2% ball joint dust cover severely…
- 2003 85.2% ball joint dust cover severely…
- 2004 86.7% windscreen damaged but not…
- 2005 86.1% coil spring fractured or broken
- 2006 85.4% coil spring fractured or broken
- 2007 85.5% coil spring fractured or broken
- 2008 86.7% coil spring fractured or broken
- 2009 85.3% coil spring fractured or broken
- 2010 84.9% windscreen damaged but not…
- 2011 88.3% coil spring fractured or broken
- 2012 86.2% has a cut in excess of the…
- 2013 86.2% malfunction indicator lamp…
- 2014 88.8% has a cut in excess of the…
- 2015 89.6% windscreen damaged but not…
- 2016 91.4% has a cut in excess of the…
- 2017 92.2% windscreen damaged but not…
- 2018 92.0% windscreen damaged but not…
- 2019 93.5% has a cut in excess of the…
- 2020 93.7% has a cut in excess of the…
- 2021 88.5%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 Sl 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
- Nissan Navara 88.5%
- BMW 840I 88.5%
- Hyundai I30 88.5%
- Ford Mondeo 88.4%
- Kia Ceed 88.8%
- Toyota Hilux Invincible D-4D 88.8%
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 Sl 8 failure items · 6 advisories · 8 inspection categories · mileage brackets · all of it in the page, none of it above the fold
Every inspection category
Shares of the 30 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 | 17 | 56.70% | 19.76% | +36.94 |
| Suspension | 3 | 10.00% | 20.98% | −10.98 |
| Road Wheels | 3 | 10.00% | 0.75% | +9.25 |
| Brakes | 2 | 6.70% | 20.89% | −14.19 |
| Lamps, reflectors and electrical equipment | 2 | 6.70% | 12.21% | −5.51 |
| Visibility | 1 | 3.30% | 4.97% | −1.67 |
| Non-component advisories | 1 | 3.30% | 4.18% | −0.88 |
| Steering | 1 | 3.30% | 2.57% | +0.73 |
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 | 5.1% | £45–95 |
| Fractured Road Wheels | Major | 3.9% | £20–55 |
| Headlamp aim too low Lamps, reflectors and electrical equipment | Major | 2.6% | £30–80 |
| Ball joint excessively worn Suspension | Major | 1.3% | £18–45 |
| Has a bulge, caused by separation or partial failure of its structure Tyres | Major | 1.3% | £45–95 |
| Rigid brake pipes excessively corroded Brakes | Major | 1.3% | £80–180 |
| Steering box has excessive free play detected at the steering wheel (steering box fitted) Steering | Major | 1.3% | £60–200 |
| Windscreen damaged but not adversely affecting driver's view Visibility | Minor | 1.3% | £80–200 |
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 | 7.7% | £45–95 |
| Has a cut in excess of the requirements deep enough to reach the ply or cords Tyres | Advisory | 5.1% | £45–95 |
| Tread depth below requirements of 1.6mm Tyres | Advisory | 2.6% | £45–95 |
| Ball joint excessively worn Suspension | Advisory | 1.3% | £18–45 |
| Flexible brake hoses excessively deteriorated Brakes | Advisory | 1.3% | £25–70 |
| Non-component advisories Nail in tyre Non-component advisories | Advisory | 1.3% | £45–95 |
Pass rate by mileage
| Mileage | Tests | Pass rate | Median odometer |
|---|---|---|---|
| 0-30k | 65 | 95.4% | 15,494 mi |
| 30-60k | 9 | 66.7% | 37,204 mi |
| 60-90k | 1 | 0.0% | 85,213 mi |
| 120k+ | 3 | 33.3% | 130,291 mi |
Source: 78 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 Sl MOT questions
What is the MOT pass rate for a 2021 Mercedes-Benz Sl?
88.5% of the 78 2021 Mercedes-Benz Sl tests in this dataset passed, against a national average of 91.2% for cars first used in 2021. First-attempt pass rate: 88.7%.
What are the most common MOT failures on a 2021 Mercedes-Benz Sl?
The three most recorded items are has a cut in excess of the requirements deep enough to reach the ply or cords (5.13%), fractured (3.85%), headlamp aim too low (2.56%). Percentages are the share of tests on this vehicle that recorded the item.
Does mileage affect the 2021 Mercedes-Benz Sl MOT pass rate?
Yes. Cars under 30,000 miles passed 95.4% of the time, falling to 33.3% for those over 120,000 miles. The median 2021 Mercedes-Benz Sl in this dataset had covered 17,104 mi.