Smart Forfour MOT Failure Rate & Common Faults
We analysed 24,602 MOT tests on the Smart Forfour carried out in 2023. 26% failed at the first attempt, which is slightly below the 29% average across all cars in the same data. Put another way, about 7 in 10 Forfours passed first time.
Results cover cars first registered from 2004 to 2019. Compared with other cars of the same age, 2004 models did best (57% passed, +1.2 points against the average for 19-year-old cars), while 2015 models fared worst (70%, −5.1 points). Tested cars had covered 43,610 miles on average, against 73,145 across all cars.
The most common reason for failure was lights and electrics, found on 7.9% of tests (slightly below the 11.3% seen across all cars). The single most frequent fault was "not working", on 4.0% of tests.
- MOT tests analysed
- 24,602
- First-time pass rate
- 74%
- All cars: 71%
- Versus all cars
- +3.0 points
- Average mileage at test
- 43,610
- All cars: 73,145
Checking a particular Forfour?
See its own MOT history, advisories and mileage for free.
Forfour MOT pass rate by year
Older cars fail more often, so each year is compared with all cars of the same age. Bars above the dashed line did better than average for their age.
| First registered | Tests | Pass rate | All cars, same age | Difference | Avg mileage |
|---|---|---|---|---|---|
| 2019 | 1,955 | 85% | 86% | −1.2 points | 20,748 |
| 2018 | 3,863 | 83% | 84% | −0.8 points | 26,363 |
| 2017 | 4,796 | 79% | 82% | −2.3 points | 33,717 |
| 2016 | 5,284 | 74% | 79% | −4.2 points | 39,602 |
| 2015 | 5,549 | 70% | 75% | −5.1 points | 46,109 |
| 2007 | 126 | 56% | 57% | −0.6 points | 91,492 |
| 2006 | 1,234 | 57% | 56% | +0.8 points | 95,122 |
| 2005 | 1,297 | 56% | 56% | −0.3 points | 97,355 |
| 2004 | 451 | 57% | 56% | +1.2 points | 104,367 |
Why the Smart Forfour fails its MOT
The share of tests with at least one failure in each area, compared with all cars.
| Failure area | Forfour | All cars |
|---|---|---|
| Lights and electrics | 7.9% | 11.3% |
| Tyres | 7.6% | 6.3% |
| Visibility | 6.3% | 4.8% |
| Suspension | 5.4% | 8.9% |
| Brakes | 4.2% | 6.8% |
| Noise, emissions and leaks | 3.4% | 3.1% |
| Body and structure | 2.1% | 3.5% |
| Steering | 0.7% | 1.8% |
| Seatbelts and airbags | 0.4% | 1.0% |
| Number plates and VIN | 0.3% | 0.4% |
Top 10 specific failure reasons
- 1not working4.0%
- 2does not clear the windscreen effectively3.6%
- 3tread depth below requirements of 1.6mm3.0%
- 4ball joint excessively worn2.7%
- 5provides insufficient washer liquid1.9%
- 6less than 1.5 mm thick1.8%
- 7Lambda reading after 2nd fast idle outside specified limits1.7%
- 8has ply or cords exposed1.5%
- 9fractured or broken1.3%
- 10inoperative or indicates a malfunction1.3%
Common Forfour MOT advisories
Advisories don't cause a fail, but they show what's wearing out. On a used Forfour, check whether these have been dealt with. Read our guide to MOT advisories.
| Advisory | Area | Share of tests |
|---|---|---|
| tread depth below requirements of 1.6mm | Tyres | 16.1% |
| in such a condition that it is seriously weakened | Brakes | 10.0% |
| has a tear, caused by separation or partial failure of its structure | Tyres | 9.3% |
| less than 1.5 mm thick | Brakes | 6.1% |
| significantly and obviously worn | Brakes | 3.9% |
| ball joint excessively worn | Suspension | 2.7% |
| tread pattern not visible over the whole tread area when minimum depth required is 1.0mm | Tyres | 2.4% |
| corroded so that its cross sectional area is reduced and seriously weakened | Suspension | 1.9% |
| inscription illegible | Number plates and VIN | 1.8% |
| Child Seat fitted not allowing full inspection of adult belt | Non-component advisories | 1.6% |
Tips to help your Forfour pass
Based on where Forfours most often fail. For a full list, use our pre-MOT checklist.
Lights and electrics · 7.9% of Forfour tests
Walk round every light
With a helper, check headlights on dipped and main beam, sidelights, brake lights, indicators, the rear fog light and the number plate lamp. Replace blown bulbs in pairs and make sure no lenses are cracked.
Visibility · 6.3% of Forfour tests
Clear the view
Replace wiper blades that smear, fill the washer bottle and get chips in the windscreen repaired early, especially in the area directly in front of the driver.
Compare with other models
Is the Forfour ULEZ compliant? See the Smart Forfour ULEZ check, or view all Smart models.
Other Smart models
Models with similar pass rates
About this data
Based on 24,602 first MOT tests of the Smart Forfour carried out in 2023.
Source: DVSA anonymised MOT test data (contains public sector information licensed under the Open Government Licence v3.0). First attempts on cars only; “pass rate” means passing first time. Averages cover all 32,735,164 cars tested (71% passed), and years with under 50 tests are hidden.
Learn more about how our data works.
Frequently asked questions
Answers from 24,602 first MOT tests of the Smart Forfour.
What is the Smart Forfour MOT failure rate?
In our data, 26% of 24,602 first MOT attempts on the Smart Forfour ended in a fail, compared with 29% for all cars.
What is the most common reason a Smart Forfour fails its MOT?
The most common failure areas were lights and electrics (7.9% of tests), tyres (7.6% of tests), visibility (6.3% of tests).
Which Forfour year has the best MOT pass rate?
Allowing for age, 2004 cars performed best: 57% passed first time, +1.2 points against the average for 19-year-old cars. The weakest was 2015, at 70% (−5.1 points).
How many miles had a typical Smart Forfour covered at its MOT?
The average was 43,610 miles, against 73,145 for all cars tested. 2019 cars averaged 20,748 miles and 2004 cars 104,367.
What is the most common MOT advisory on the Smart Forfour?
"tread depth below requirements of 1.6mm" was recorded on 16.1% of tests, in the tyres area. 7.6% of Forfours failed in that area too.
How can I check a specific Forfour's MOT history?
Enter its registration in our free MOT check. Across the 24,602 Forfours in our data, first-time pass rates ranged from 56% to 85% by year, so one car's own record says more than the average.
Related guides
- MOT · 6 min readPre-MOT checklist: 20 things to check yourself before the testTwenty quick checks, grouped by area, that you can do on your driveway in under half an hour. No tools beyond a coin and a helper needed for most.Read the guide
- MOT · 4 min readTyre tread depth and the MOT: the legal limit and how to check6.3% of cars failed their 2023 MOT on tyres. The 1.6mm legal limit, what testers look for beyond tread, and a one-minute check with a 20p coin.Read the guide
- MOT · 6 min readThe most common reasons cars fail their MOT (and how to avoid them)Lights alone failed 11.3% of cars at their 2023 MOT, more than any other area. The common failure areas, ranked, and the driveway checks that prevent them.Read the guide
Check any Forfour's MOT history
Every test, failure, advisory and recorded mileage for a specific car. Free, from official DVSA data.