Common problems
Smart Roadster common problems
What MOT testers find on the Smart Roadster: the parts that fail or get advisories most often at each age, against all cars of the same age. From 10,369 DVSA MOT tests taken 2022 to 2025.
MOT data updated
At 19 years, the most tested age
What stands out
- No part area of the Smart Roadster fails more than 1 point per 100 MOTs above all cars at 19 years old (n=2,777; all cars n=2,479,858).
- Suspension fails are less common: 7.9 per 100 MOTs against 16.9 for all cars at the same age.
- The fail item testers record most often at 19 years: side/position light not working, on 3.6 per 100 MOTs (all cars 5.4).
- The most common advisory or minor defect: rigid brake pipes: corroded, covered in grease or other material, on 19.5 per 100 MOTs.
Problems by part at 19 years
How many of every 100 MOTs found a fail, or an advisory or minor defect, in each area. A test with faults in two areas counts in both.
| Area | Fails | All cars | Advisories | All cars |
|---|---|---|---|---|
| Lights and electrics | 16.6 | 21.5 | 14.6 | 17.9 |
| Brakes | 8.0 | 13.3 | 32.7 | 33.3 |
| Suspension | 7.9 | 16.9 | 26.9 | 35.4 |
| Windscreen, wipers and mirrors | 4.5 | 7.5 | 3.8 | 6.3 |
| Tyres | 3.5 | 6.8 | 15.7 | 26.9 |
| Exhaust, emissions and leaks | 3.2 | 7.0 | 12.3 | 14.7 |
| Body and structure | 2.5 | 9.0 | 3.0 | 15.2 |
| Steering | 2.1 | 4.1 | 5.1 | 6.0 |
| Seat belts and airbags | 1.9 | 2.9 | 0.5 | 1.4 |
| Road wheels | 0.6 | 0.5 | 3.5 | 1.2 |
| Number plates and VIN | 0.5 | 0.7 | 2.8 | 5.9 |
What testers fail most on the Roadster at 19 years
| Item | Area | Per 100 MOTs | All cars | Typical repair (estimate) |
|---|---|---|---|---|
| Side/position light not working | Lights and electrics | 3.6 | 5.4 | £10 to £47 per lamp |
| Brake light not working | Lights and electrics | 2.8 | 4.0 | £10 to £47 per lamp |
| Horn: not working | Lights and electrics | 2.8 | 0.6 | £33 to £113 per car (rough guide) |
| Dipped headlight not working | Lights and electrics | 2.4 | 2.0 | £18 to £86 per lamp |
| Wipers not clearing screen | Windscreen, wipers and mirrors | 2.3 | 3.3 | £15 to £30 per blade |
| Individual direction indicators: incorrect colour | Lights and electrics | 2.2 | 1.0 | £10 to £47 per lamp |
| Rear fog lamp: not working | Lights and electrics | 2.1 | 1.2 | £10 to £47 per lamp |
| Rigid brake pipes: excessively corroded | Brakes | 1.8 | 2.5 | £137 to £392 per car (rough guide) |
| Airbag (SRS) warning light on | Seat belts and airbags | 1.8 | 1.4 | diagnosis from £39 (rough guide) |
| Coil spring broken | Suspension | 1.4 | 2.8 | £64 to £236 per spring (rough guide) |
Early warnings: advisories and minor defects at 19 years
Advisories and minor defects are recorded, but the car still passes. Across all cars, a part with an advisory or minor defect failed at the next MOT 5.5 times in 100 (n=88,666,940 pairs of consecutive MOTs), against 0.3 times in 100 when the same part had none (n=12,936,860,350).
| Item | Area | Per 100 MOTs | All cars | If it needs replacing (estimate) |
|---|---|---|---|---|
| Rigid brake pipes: corroded, covered in grease or other material | Brakes | 19.5 | 14.1 | £137 to £392 per car (rough guide) |
| Engine oil leaks: leak, but not excessive | Exhaust, emissions and leaks | 12.0 | 13.2 | |
| Brake discs: worn, pitted or scored, but not seriously weakened | Brakes | 11.3 | 10.8 | £148 to £376 per axle (rough guide) |
| Tyre condition: slightly damaged/cracking or perishing | Tyres | 9.3 | 9.9 | £88 to £145 per tyre |
| Coil spring: corroded | Suspension | 7.9 | 7.9 | |
| Registration plate lamp(s): inoperative in the case of multiple lamps or light sources | Lights and electrics | 6.2 | 5.6 | |
| Tread depth: worn close to legal limit/worn on edge | Tyres | 6.2 | 16.6 | £88 to £145 per tyre |
| Shock absorbers: has a slightly worn bush | Suspension | 4.9 | 0.7 | £122 to £484 per axle (pair) (rough guide) |
| Individual direction indicators: slightly discoloured | Lights and electrics | 4.6 | 1.9 | £10 to £47 per lamp |
| Flexible brake hoses: slightly deteriorated | Brakes | 4.4 | 2.1 |
Repair estimates are a guide for an independent garage: labour at the national median local garage rate (median £78 an hour from 65 garages, ONS price quotes) times estimated labour hours, plus a parts band. Labour hours and most parts bands are estimates, not quotes, and prices vary by model, engine and region. A warning light fault shows the cost of the diagnosis only.
How problems change with age
| Age | Tests (n) | Lights and electrics | Brakes | Suspension |
|---|---|---|---|---|
| 17 years | 1,347 | 17.8 | 8.0 | 7.5 |
| 18 years | 2,612 | 16.4 | 8.8 | 8.3 |
| 19 years | 2,777 | 16.6 | 8.0 | 7.9 |
| 20 years | 2,225 | 17.4 | 8.3 | 8.4 |
| 21 years | 1,408 | 17.4 | 8.7 | 8.0 |
What to check on a viewing
On the Smart Roadster, testers most often record side/position light not working; brake light not working; horn: not working. Look at these first, then the areas below.
Lights and electrics
- With someone outside, try every light: dipped and main beam, indicators, brake lights, fog lights and number plate lamps.
- Check that the warning lights come on with the ignition and go out once the engine runs.
- Look for misted, cracked or yellowed headlamp lenses.
Brakes
- On the test drive the car should stop in a straight line without pulling, juddering or grinding.
- Look at the discs through the wheels for a deep lip, heavy rust or scoring.
- Check that the handbrake or electronic parking brake holds the car on a slope.
- Ask when the pads, discs and brake fluid were last changed, and for the receipts.
Suspension
- Listen for knocks or clonks over speed bumps and rough roads on the test drive.
- Push down hard on each corner: the car should settle at once rather than keep bouncing.
- Look behind the wheels for broken or heavily rusted coil springs and split rubber bushes.
- Check that the car sits level and that no tyre is worn on one edge only.
Ask for the car's MOT history and service record: advisories that repeat from one year to the next show what has been left. GOV.UK MOT history.
Questions
What are the most common problems on the Smart Roadster?
At 19 years, the age with the most MOT tests (2,777), the fail items testers record most often on the Smart Roadster are side/position light not working (3.6 per 100 MOTs), brake light not working (2.8 per 100 MOTs), horn: not working (2.8 per 100 MOTs). The most common advisories or minor defects are rigid brake pipes: corroded, covered in grease or other material (19.5) and engine oil leaks: leak, but not excessive (12.0).
Which parts of the Smart Roadster fail more often than on other cars?
None by more than 1 point per 100 MOTs at 19 years, compared with 2,479,858 MOTs of all cars the same age.
Smart Roadster problems by area
More on the Smart Roadster
Other Smart models
The all cars figures cover all class 4 vehicles (cars and light vans) tested at the same age.
Looking at a Smart Roadster?
These figures describe the model, not the car in front of you. Found one you might buy? See what the VetTheCar Buying Report covers, or use the tools that work without a registration.
See a sample report Car tools · MOT fail rates by model · Compare models by MOT record
Repair estimates: ONS consumer price quotes for local garage labour (09/2025 to 08/2026), the MOT inspection manual for defect wording, and estimated labour hours and parts bands. Not affiliated with or endorsed by ONS.
Source
Contains public sector information licensed under the Open Government Licence v3.0. Source: DVSA anonymised MOT test data, class 4 normal MOT tests, 2022 to 2025. MOT data updated 28 September 2026.
Not affiliated with or endorsed by DVSA. How we calculate these figures · Data sources