CARMOTIQ Model Research Report
Mercedes-Benz S Class
2016–2021
The Mercedes-Benz S Class MOT pass rate for cars first registered 2016–2021 is 90.7% across 37,782 official UK DVSA tests. 90.7% of Mercedes-Benz S Class MOT tests in this age band end in a pass — a solid headline for a car that magazines still describe as the benchmark luxury saloon. Peel back the 29,589 defect notes recorded alongside those tests, though, and upkeep — not engineering failure — carries most of the weight.
Unlike a registration check, this report analyses how thousands of similar Mercedes-Benz S Class models have performed at MOT over time—not just one vehicle.
Report Dataset
- Official UK DVSA MOT tests analysed
- 37,782
- Recorded defect notes
- 29,589
- Registration era
- 2016–2021
- Coverage
- United Kingdom
- Snapshot
- 17 August 2026
- Research method
- Aggregated model-level MOT analysis
MOT pass rate
90.7%
of MOT tests passed
MOT tests analysed
37,782
Defect notes recorded
29,589
Key Findings
Mercedes-Benz S Class (2016–2021)
- Mercedes-Benz S Class achieves a 90.7% MOT pass rate across 37,782 UK DVSA tests for 2016–2021 registrations.
- 17,727 defect notes — about 60% of the total — are classified as owner maintenance, with tyre wear alone responsible for 9,394 entries.
- Systemic faults total 1,109 notes; engine management indicator lamp issues (187 and 111 counts on separate test codes) and tyre-pressure monitoring faults (92) lead that category.
- Wear-and-age items account for 5,890 notes, led by shock absorber oil misting (29) and brake disc surface wear (11).
- Owner-maintenance severity includes 1,869 Dangerous and 1,202 Major classified items — predominantly tied to neglected tyres and related safety checks.
Mercedes-Benz S Class Research Summary
Carmotiq aggregates official DVSA MOT records for the Mercedes-Benz S Class at make-and-model level — every test in the dataset for this registration band, not a single GOV.UK history lookup. Of 37,782 tests, 90.7% pass outright, which sits comfortably for a five-to-ten-year-old luxury saloon. Yet nearly 30,000 defect notes accompany those results, and the split is telling: owner maintenance dominates at 17,727 entries, wear-and-tear contributes 5,890, systemic issues 1,109, and a further 4,863 fall outside those three buckets.
For a buyer weighing a used S Class against its showroom reputation, the actionable detail is where those notes concentrate. Tyres — worn to the legal limit or feathered on the edge — appear 9,394 times, making basic tyre care the clearest forecourt check. Systemic entries remain a smaller share but cluster around warning-lamp and monitoring faults: engine management indicators (298 notes across two codes), tyre-pressure monitoring (92), and supplementary restraint system warnings (76). Year-on-year, owner-maintenance notes climb sharply as the fleet ages — from 105 in 2017 to 2,916 in 2022 — while wear-and-tear entries follow the same curve. Luxury reviews emphasise comfort and technology; the MOT record says conditional pass rates hold up, but only if previous keepers stayed on top of tyres, fluids, and warning-lamp faults before test day.
What this doesn't tell you
This report describes model-level MOT trends, not the condition of any individual vehicle.
Two identical Mercedes-Benz S Class models can have very different maintenance histories.
Use this report to understand common patterns before inspecting a specific car.
How we classify MOT faults
We group recorded DVSA defect wording into four research categories to help identify whether issues are more likely to reflect routine maintenance, expected wear, recurring model patterns or miscellaneous inspection outcomes.
- Owner maintenance
- Defects often linked to day-to-day upkeep — for example tyres, lamps, washers and other items a careful owner can usually prevent or fix promptly.
- Wear & tear
- Age- and mileage-related deterioration that accumulates with normal use, even when a car has been looked after.
- Systemic
- Recurring wording and patterns that appear across the model fleet and may point to design, component or known-model tendencies rather than one careless owner.
- Other
- Inspection outcomes that do not sit cleanly in the three groups above, including mixed or less classifiable defect notes.
How MOT failures break down
Share of recorded defect notes by category for Mercedes-Benz S Class in this age band (not MOT tests and not number of vehicles).
- Owner maintenance
59.9% · 17,727
defect notes
- Wear & tear
19.9% · 5,890
defect notes
- Systemic
3.7% · 1,109
defect notes
- Other
16.4% · 4,863
defect notes
Severity mix
How those defect notes were graded — advisory, minor, major or dangerous — summed across categories for this model band.
Advisory
23,458
defect notes
Minor
1,194
defect notes
Major
2,815
defect notes
Dangerous
2,122
defect notes
Most Common Owner-Maintenance Faults
DVSA wording grouped as owner maintenance for this model and age band.
Tyre worn close to legal limit/worn on edge
- Recorded
- 9,394 MOT defect notes
- DVSA code
- 5.2.3 (e)
What it means
Tread is close to (or at) the legal minimum, or wear is concentrated on an edge. That often points to alignment, pressure or suspension issues as well as simple age.
Why it happens
Under-inflation, poor alignment, aggressive driving or simply delayed replacement push tread below a safe/legal profile.
Buyer tip
Measure tread across the full width, check tyre age (DOT date) and look for uneven inner-edge wear.
Severity
Usually maintenance related
Windscreen washer not working
- Recorded
- 354 MOT defect notes
- DVSA code
- 3.5 (a)
What it means
Washer jets are not delivering fluid. Testers need a clear screen; empty reservoirs, blocked jets or failed pumps are common.
Why it happens
Empty bottles, frozen/blocked jets, split pipes or a failed pump stop fluid reaching the screen.
Buyer tip
Top up fluid, test the jets on the driveway, and check for cracked bottles or split pipes in the engine bay.
Severity
Usually maintenance related
Headlamp aim too low
- Recorded
- 226 MOT defect notes
- DVSA code
- 4.1.2 (a)
What it means
This MOT defect usually indicates incorrect headlamp alignment following adjustment, suspension movement or repair work.
Why it happens
Aim drifts after suspension work, bumper repairs, bulb changes or simply from road vibration over time.
Buyer tip
Check beam alignment during inspection and ask whether the lamps were aimed after any recent suspension or bodywork.
Severity
Usually maintenance related
Tyre worn close to the legal limit
- Recorded
- 116 MOT defect notes
- DVSA code
- 4.1.E.1
What it means
Tread is close to (or at) the legal minimum, or wear is concentrated on an edge. That often points to alignment, pressure or suspension issues as well as simple age.
Why it happens
Under-inflation, poor alignment, aggressive driving or simply delayed replacement push tread below a safe/legal profile.
Buyer tip
Measure tread across the full width, check tyre age (DOT date) and look for uneven inner-edge wear.
Severity
Usually maintenance related
Tyre not fitted in accordance with side wall instructions
- Recorded
- 25 MOT defect notes
- DVSA code
- 5.2.3 (i)
What it means
A tyre is fitted against its sidewall instructions (for example direction of rotation or inside/outside face).
Why it happens
Fitting errors at tyre change — directionals or asymmetric tyres mounted the wrong way round.
Buyer tip
Ask a tyre fitter to confirm orientation marks before you accept the car.
Severity
Usually maintenance related
Brake pad(s) wearing thin
- Recorded
- 22 MOT defect notes
- DVSA code
- 3.5.1g
What it means
This wording appears on DVSA MOT records for this model. It flags a tester-observed defect or advisory that can affect safety, legality or a future pass.
Why it happens
These issues often build up when routine checks are skipped between services — tyres, lamps and washers are typical examples.
Buyer tip
Ask the seller for invoices covering this item, and have an independent inspector confirm whether it is still present.
Severity
Usually maintenance related
Tyre(s) of different sizes are fitted on the same axle.
- Recorded
- 17 MOT defect notes
- DVSA code
- 5.2.3 (b)
What it means
Mismatched tyre sizes on the same axle can upset handling, ABS/ESC behaviour and legality.
Why it happens
Emergency replacements or mismatched spare use leave different sizes on one axle.
Buyer tip
Confirm matching size, load and speed ratings on each axle before you drive away.
Severity
Usually maintenance related
Tyre obviously under inflated
- Recorded
- 12 MOT defect notes
- DVSA code
- 5.2.3 (l)
What it means
This wording appears on DVSA MOT records for this model. It flags a tester-observed defect or advisory that can affect safety, legality or a future pass.
Why it happens
These issues often build up when routine checks are skipped between services — tyres, lamps and washers are typical examples.
Buyer tip
Ask the seller for invoices covering this item, and have an independent inspector confirm whether it is still present.
Severity
Usually maintenance related
Most Common Wear & Tear Faults
DVSA wording grouped as wear and tear for this model and age band.
Shock absorbers has light misting of oil
- Recorded
- 29 MOT defect notes
- DVSA code
- 5.3.2 (b)
What it means
A damper mounting bush is worn, which can cause knocks, vague handling and accelerated tyre wear.
Why it happens
Rubber bushes harden and tear with age, road salt and repeated suspension movement.
Buyer tip
Listen for clunks over speed bumps and have a mechanic check top mounts and lower bushes.
Severity
Usually wear related
brake disc worn, pitted or scored, but not seriously weakened
- Recorded
- 11 MOT defect notes
- DVSA code
- 3.5.1i
What it means
A brake disc is contaminated, scored or otherwise not in a serviceable condition for consistent braking.
Why it happens
Worn pads, rust lip, oil contamination or delayed disc replacement leave an uneven braking surface.
Buyer tip
Check disc faces through the wheels and ask for pad/disc measurements if the car is due brakes soon.
Severity
Usually wear related
Seat belt webbing slightly damaged or frayed
- Recorded
- 8 MOT defect notes
- DVSA code
- 7.1.2 (b)
What it means
Seat-belt webbing is frayed or lightly damaged, which can weaken the belt in a crash.
Why it happens
Abrasion at guides, trapped belts or age fray the webbing fibres.
Buyer tip
Pull each belt fully out and inspect for cuts, fraying and weak retraction.
Severity
Usually wear related
Lower Shock absorbers has a slightly worn bush
- Recorded
- 7 MOT defect notes
- DVSA code
- 5.3.2 (c)
What it means
A damper mounting bush is worn, which can cause knocks, vague handling and accelerated tyre wear.
Why it happens
Rubber bushes harden and tear with age, road salt and repeated suspension movement.
Buyer tip
Listen for clunks over speed bumps and have a mechanic check top mounts and lower bushes.
Severity
Usually wear related
Rear Seat belt buckle slightly damaged
- Recorded
- 4 MOT defect notes
- DVSA code
- 7.1.2 (d)
What it means
This wording appears on DVSA MOT records for this model. It flags a tester-observed defect or advisory that can affect safety, legality or a future pass.
Why it happens
Components age with mileage and road use, even when a car has been looked after carefully.
Buyer tip
Ask the seller for invoices covering this item, and have an independent inspector confirm whether it is still present.
Severity
Usually wear related
Rear Brake lever pivots slightly worn
- Recorded
- 2 MOT defect notes
- DVSA code
- 1.1.1 (b)
What it means
This wording appears on DVSA MOT records for this model. It flags a tester-observed defect or advisory that can affect safety, legality or a future pass.
Why it happens
Components age with mileage and road use, even when a car has been looked after carefully.
Buyer tip
Ask the seller for invoices covering this item, and have an independent inspector confirm whether it is still present.
Severity
Usually wear related
Exhaust emissions likely to be affected by an exhaust leak
- Recorded
- 2 MOT defect notes
- DVSA code
- 8.2.2.1 (b)
What it means
Emissions could not be completed cleanly, or a leak is likely to upset the reading. Common causes include exhaust leaks, misfires, DPF issues or an engine that will not idle correctly.
Why it happens
Leaks before the sample point, misfires, DPF problems or unstable idle prevent a valid emissions result.
Buyer tip
Listen for blow-by at joints, check for recent exhaust/DPF work, and avoid cars that need “easier” emissions excuses.
Severity
Usually wear related
Front suspension has slight play in a lower suspension ball joint
- Recorded
- 1 MOT defect notes
- DVSA code
- 2.5.B.1a
What it means
This wording appears on DVSA MOT records for this model. It flags a tester-observed defect or advisory that can affect safety, legality or a future pass.
Why it happens
Components age with mileage and road use, even when a car has been looked after carefully.
Buyer tip
Ask the seller for invoices covering this item, and have an independent inspector confirm whether it is still present.
Severity
Usually wear related
Most Common Systemic Faults
DVSA wording grouped as systemic patterns for this model and age band.
Engine MIL inoperative or indicates a malfunction
- Recorded
- 187 MOT defect notes
- DVSA code
- 8.2.2.2 (g)
What it means
The engine management warning lamp is on or not working. Stored faults can affect emissions, drivability and future MOT results.
Why it happens
Sensors, emissions equipment or wiring faults store codes that illuminate the MIL.
Buyer tip
Ask for a diagnostic printout and proof that the underlying fault — not just the lamp — was fixed.
Severity
Often a recurring model pattern
Engine MIL inoperative or indicates a malfunction
- Recorded
- 111 MOT defect notes
- DVSA code
- 8.2.1.2 (h)
What it means
The engine management warning lamp is on or not working. Stored faults can affect emissions, drivability and future MOT results.
Why it happens
Sensors, emissions equipment or wiring faults store codes that illuminate the MIL.
Buyer tip
Ask for a diagnostic printout and proof that the underlying fault — not just the lamp — was fixed.
Severity
Often a recurring model pattern
Tyre pressure monitoring system malfunctioning or obviously inoperative
- Recorded
- 92 MOT defect notes
- DVSA code
- 5.2.3 (h)
What it means
The tyre pressure monitoring system is reporting a fault or is clearly not working, so you may not get a dashboard warning of under-inflation.
Why it happens
Flat battery sensors after tyre changes, damaged valves or control-module faults are common.
Buyer tip
Confirm whether sensors need replacing after recent tyre or wheel work, and check pressures manually anyway.
Severity
Often a recurring model pattern
Supplementary restraint system warning lamp indicates a fault
- Recorded
- 76 MOT defect notes
- DVSA code
- 7.1.6 (a)
What it means
The airbag/SRS warning lamp indicates a fault. Restraint systems may not deploy correctly in a collision.
Why it happens
Clock-spring, sensor or module faults — sometimes after prior accident repairs — set SRS warnings.
Buyer tip
Require a specialist SRS diagnosis — do not accept a bulb removed or lamp covered up.
Severity
Often a recurring model pattern
Driver's airbag obviously inoperative
- Recorded
- 9 MOT defect notes
- DVSA code
- 7.1.5 (c)
What it means
The airbag/SRS warning lamp indicates a fault. Restraint systems may not deploy correctly in a collision.
Why it happens
Clock-spring, sensor or module faults — sometimes after prior accident repairs — set SRS warnings.
Buyer tip
Require a specialist SRS diagnosis — do not accept a bulb removed or lamp covered up.
Severity
Often a recurring model pattern
Electronic stability control warning lamp indicates a fault
- Recorded
- 9 MOT defect notes
- DVSA code
- 7.12 (e)
What it means
Electronic stability control is reporting a fault or related wiring damage. Stability aids may be unavailable.
Why it happens
Sensor, wiring or module faults disable ESC and light the dashboard warning.
Buyer tip
Check for ESC/ASR lamps on ignition and ask for a scan if any warning stays on.
Severity
Often a recurring model pattern
Brake fluid warning lamp illuminated
- Recorded
- 7 MOT defect notes
- DVSA code
- 1.1.10 (f)
What it means
This wording appears on DVSA MOT records for this model. It flags a tester-observed defect or advisory that can affect safety, legality or a future pass.
Why it happens
When similar DVSA wording appears across many examples, it can reflect shared components or recurring model tendencies rather than one careless owner.
Buyer tip
Ask the seller for invoices covering this item, and have an independent inspector confirm whether it is still present.
Severity
Often a recurring model pattern
Brake pipe corroded, covered in grease or other material
- Recorded
- 4 MOT defect notes
- DVSA code
- 1.1.11 (c)
What it means
A brake pipe is damaged or heavily corroded. Pipe failure can cause sudden loss of braking effort.
Why it happens
Road salt, stone chips and age corrode metal pipes, especially along the underbody.
Buyer tip
Inspect metal pipes along the underbody and near calipers; corroded pipes should be replaced before you rely on the car.
Severity
Often a recurring model pattern
Recent year-by-year category counts
Defect-note totals by calendar year in the serving extract (not MOT tests, not vehicles, and not a prediction).
| Year | Owner maintenance | Wear & tear | Systemic | Other |
|---|---|---|---|---|
| defect notes | defect notes | defect notes | defect notes | |
| 2021 | 2,256 | 544 | 102 | 526 |
| 2022 | 2,916 | 805 | 144 | 662 |
| 2023 | 2,881 | 958 | 175 | 683 |
| 2024 | 2,872 | 1,136 | 192 | 750 |
| 2025 | 2,664 | 1,236 | 234 | 746 |
| 2026 | 1,351 | 603 | 106 | 391 |
Buying a used Mercedes-Benz S Class: practical MOT checks
- Inspect all four tyres for edge wear and tread depth — tyre defects account for 9,394 recorded notes, the single largest item in the dataset.
- With the engine running, confirm the engine management, SRS, tyre-pressure and stability-control warning lamps all behave normally before you drive.
- Check the windscreen washer works and headlamp aim looks correct — both appear repeatedly in maintenance-related MOT notes.
- Look for advisory mentions on shock absorbers and brake discs, which are the most common wear-related items as these cars move through their second MOT cycle.
Frequently asked questions
- What is the Mercedes-Benz S Class MOT pass rate for 2016–2021 registrations?
- In Carmotiq's extract, the Mercedes-Benz S Class records a 90.7% MOT pass rate across 37,782 DVSA tests for cars in the 5–10 years old registration era.
- What causes most Mercedes-Benz S Class MOT defect notes?
- Owner-maintenance-related items account for 17,727 of 29,589 recorded defect notes — roughly six in ten. Tyres worn close to the legal limit or worn on the edge alone appear 9,394 times, far ahead of any other single fault.
- Does a strong luxury-car reputation mean fewer serious MOT issues?
- Not automatically. Owner-maintenance notes include 1,869 Dangerous and 1,202 Major severity items in this dataset, while systemic faults such as inoperative engine management indicator lamps (298 combined notes across two test codes) appear independently of routine upkeep.