City car · 2001–2021 cars
Smart Forfour reliability
The Smart Forfour fails 25.6% of first MOT tests, 30% more MOT fails than the average car its age and mileage, based on 81,951 DVSA MOT tests from 2022 to 2024.
Checking a Smart Forfour before you buy?
- first-time MOT fail rate (all cars: 28.4%)
- 25.6%
- first-time MOT fail rate (all cars: 28.4%)
- fails than cars of the same age and mileage
- 30% more
- fails than cars of the same age and mileage
- MOT tests analysed, 2022 to 2024
- 81,951
- MOT tests analysed, 2022 to 2024
- typical miles a year, from MOT readings
- 5,700
- typical miles a year, from MOT readings
MOT fail rate by age
How the Smart Forfour ages
Each point is the share of Smart Forfours of that age that failed their MOT first time, against all cars of the same age.
| Age at MOT (years) | Smart Forfour | All cars |
|---|---|---|
| 3 | 14.4% | 12.3% |
| 4 | 16.6% | 14.1% |
| 5 | 19.7% | 16.4% |
| 6 | 22.4% | 19.1% |
| 7 | 26.9% | 22.1% |
| 8 | 29.2% | 25.5% |
| 9 | 33.8% | 28.8% |
| 15 | 41.7% | 42.3% |
| 16 | 42.1% | 42.9% |
| 17 | 43.6% | 43.4% |
| 18 | 44.8% | 43.5% |
| 19 | 43.8% | 43.4% |
By year
The best and worst Smart Forfour years
2006 cars come out best and 2019 cars worst, once age and mileage are taken into account.
| First registered | Tests | Fail rate | Against same-age cars | Typical mileage |
|---|---|---|---|---|
| 2019 Forfour | 5,452 | 16.2% | 45% more fails | 19,794 |
| 2018 Forfour | 13,320 | 17.1% | 35% more fails | 24,288 |
| 2017 Forfour | 16,382 | 20.9% | 37% more fails | 31,339 |
| 2016 Forfour | 17,970 | 25.5% | 44% more fails | 37,387 |
| 2015 Forfour | 18,727 | 29.3% | 41% more fails | 43,953 |
| 2007 | 412 | 39.8% | 5% fewer fails | 87,468 |
| 2006 Forfour | 3,933 | 42.7% | 0% more fails | 92,650 |
| 2005 Forfour | 4,114 | 44.1% | 3% more fails | 96,424 |
| 2004 Forfour | 1,474 | 45% | 3% more fails | 104,582 |
Common problems
What fails most on a Smart Forfour
Its weak spot is exhaust, emissions and leaks: 119% more fails there than cars of the same age and mileage.
Fail rate by area
- Lights and electrics7.9%25% above avg
- Tyres7.4%48% above avg
- Windscreen, wipers and mirrors6.4%70% above avg
- Suspension5.5%15% above avg
- Brakes4.2%0% below avg
- Exhaust, emissions and leaks3.9%119% above avg
- Body, chassis and structure2.1%18% above avg
- Steering0.8%14% below avg
- Seat belts and airbags0.4%35% below avg
Average for cars of the same age and mileage
Top MOT failures
- 1
Wiper blade not clearing windscreen 3.49% of tests
Wipers that do not clear the windscreen reduce visibility in rain, which is a safety risk, so replace them.
- 2
Tyre tread below 1.6mm 2.67% of tests
Tread below 1.6mm is illegal and reduces grip in wet conditions, so the tyre must be replaced.
- 3
Stop lamp not working 2.36% of tests
A failed stop lamp means drivers behind cannot see when you brake, a safety risk that must be fixed.
- 4
Suspension ball joint excessively worn 1.88% of tests
A worn ball joint can fail and cause loss of steering control, so it must be replaced promptly.
- 5
Windscreen washer fluid insufficient 1.67% of tests
Washers are not supplying enough liquid, so the windscreen cannot be cleared properly, which is a safety issue.
- 6
Brake pads worn below 1.5mm 1.64% of tests
Pads worn below 1.5mm lose stopping power and can damage discs, so replacement is needed before the car is driven.
- 7
Lambda reading outside specified limits 1.61% of tests
An out-of-range lambda reading suggests poor fuel mixture or a failing catalytic converter, so diagnosis is needed.
- 8
Tyre ply or cords exposed 1.34% of tests
Exposed ply or cords can let the tyre fail suddenly, so the tyre must be replaced before the car is driven.
Most common advisories
Not a fail yet, but worth pricing in: these show up on a Smart Forfour's MOT certificate most often.
- Tyre worn close to legal limit14.3%
- Brake disc pitted or scored8.7%
- Tyre slightly damaged or cracking8.23%
- Brake pads wearing thin5.25%
- Brake discs showing some wear3.42%
- Tyre worn close to legal limit1.94%
Before you buy
What to check on a used Smart Forfour
- 1
Wiper blade not clearing windscreen
Wipers that do not clear the windscreen reduce visibility in rain, which is a safety risk, so replace them.
- 2
Tyre tread below 1.6mm
Tread below 1.6mm is illegal and reduces grip in wet conditions, so the tyre must be replaced.
- 3
Stop lamp not working
A failed stop lamp means drivers behind cannot see when you brake, a safety risk that must be fixed.
- 4
Suspension ball joint excessively worn
A worn ball joint can fail and cause loss of steering control, so it must be replaced promptly.
- 5
Every MOT since new
Look for the faults above coming back year after year: it shows how the car has been looked after.
- 6
The mileage record
A typical Smart Forfour covers about 5,700 miles a year. A big gap or a drop between MOTs is a warning sign.
- 7
Finance, stolen and write-off
The records the MOT can't show. A Full Check (£9.99) covers all three before you hand over any money.
Fuel types tested
- Petrol96.9%
- Diesel1.6%
- Electric1.5%
- LPG0%
Most common colours
Black, White, Grey, Silver, Red
Average engine size: 1.0 litres.
Compare
How the Smart Forfour compares with its rivals
| Model | Fail rate | Against same-age cars |
|---|---|---|
| Suzuki Celerio | 14.6% | 8% fewer MOT fails than the average car its age |
| Smart Fortwo | 20.8% | 7% more MOT fails than the average car its age |
| Abarth 595 | 18.6% | 16% more MOT fails than the average car its age |
| Volkswagen Fox | 47.2% | 24% more MOT fails than the average car its age |
| Fiat 500C | 31.5% | 27% more MOT fails than the average car its age |
| Smart Forfour | 25.6% | 30% more MOT fails than the average car its age |
| Renault Twingo | 36.6% | 33% more MOT fails than the average car its age |
Every city car ranked in the city car reliability index, or all Smart models.
Questions
Smart Forfour questions, answered
Is the Smart Forfour reliable?
On MOT results, the Smart Forfour is well below average: it fails 25.6% of first MOT tests, 30% more MOT fails than the average car its age and mileage. It ranks 37 of 43 city car models in our index.
What fails most on a Smart Forfour MOT?
The most common MOT failures on the Smart Forfour are wiper blade not clearing windscreen (3.49% of tests), tyre tread below 1.6mm (2.67% of tests), stop lamp not working (2.36% of tests). By area, lights and electrics fails 7.9% of its tests.
Which Smart Forfour year is the most reliable?
Among years with 1,000+ tests, 2006 cars do best (about average for its age) and 2019 cars do worst (45% more MOT fails than the average car its age).
How many miles does a Smart Forfour do a year?
A typical Smart Forfour covers about 5,700 miles a year, from the mileage recorded at its MOTs. Check the car you're looking at against that with a free mileage check.
How do I check a Smart Forfour before I buy it?
Enter its registration for a free check of its MOT history, mileage, ULEZ status and tax. Before you pay, a Full Check (£9.99) shows outstanding finance, stolen and write-off records.
Source: DVSA anonymised MOT test results, 2022 to 2024, class 4 vehicles aged 3 to 25, normal tests only. How we compare like with like: our methodology.
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