Is the Smart (mcc) Forfour reliable?

On MOT evidence the Smart (mcc) Forfour is well below average. It passes 64.8% of tests once age and mileage are accounted for, against a national average of 72.3%. That figure covers 64% of the national age and mileage range, which is enough to quote but not to rank. This measures how often the car meets the MOT standard, not how often it breaks down or what a repair costs.

What is the most common MOT failure on a Smart (mcc) Forfour?

The item recorded most often is "Tyre tread depth not in accordance with the requirements", which appears in 19.2% of failed Smart (mcc) Forfour tests. Because one failed test can list several items, these shares do not add up to 100%.

What do testers most often warn about on a Smart (mcc) Forfour?

The most common advisory is "Tyre tread depth not in accordance with the requirements", noted on 26.4% of all Smart (mcc) Forfour tests. An advisory is not a failure: it flags something that will likely need attention before the next test.

What mileage does a Smart (mcc) Forfour usually have at its MOT?

The average odometer reading recorded at test is 48,188 miles. This is the mileage across all tested examples of every age, not an annual figure, so treat it as a description of the fleet rather than a target for one car.

Does a Smart (mcc) Forfour get harder to pass as it ages?

Yes. At 6 to 8 years old, 78.1% of Smart (mcc) Forfour tests pass. By fifteen years or more, that falls to 56.5%. Nearly every model follows this pattern, which is why comparing raw pass rates between models is misleading unless age is accounted for.

Are most Smart (mcc) Forfour models petrol or diesel?

Of the Smart (mcc) Forfour cars tested, 97% are petrol, 2% are electric, 1% are diesel. Fuel type affects which items tend to fail, particularly emissions and exhaust components.

Model reliability file

Smart (mcc) Forfour MOT pass rate & common failures

From 22,245 recorded MOT tests of the Smart (mcc) Forfour, published by DVSA.

Data updated 29 July 2026

Quick answer

The Smart (mcc) Forfour passes 64.8% of MOT tests once results are adjusted for the age and mileage of the cars tested, against a national average of 72.3%. That is well below average. Based on 22,245 tests. Its most commonly recorded failure is tyre tread depth not in accordance with the requirements, which appears in 19.2% of failed tests. Cars of this model average 48,188 miles on the odometer when tested.

At a glance

Pass rate, adjusted for age and mileage

64.8%national average72.3%unadjusted72.4%range covered64%

The Forfour is 7.5 percentage points below the national pass rate once age and mileage are accounted for, which is well below average. The unadjusted figure is 72.4%; the difference is what the age and mileage of this model’s fleet was hiding.

DVSA recorded wording

Most common failure items

Share of failed Smart (mcc) Forfour tests in which each item was recorded. One failed test often lists several items, so these do not sum to 100%.

1.Tyre tread depth not in accordance with the requirements19.2%
939 occurrencesTyre worn close to the legal limit explained
2.A suspension pin, bush or joint excessively worn15.8%
770 occurrencesSuspension arm bush worn explained
3.Lambda coefficient outside the default limits or the range specified by the manufacturer13.8%
673 occurrencesEmissions above the permitted limit explained
4.Wiper blade missing or obviously not clearing the windscreen11.2%
548 occurrencesWiper or washer not working properly explained
5.A spring or spring component fractured or seriously weakened9.8%
477 occurrencesRoad spring broken or fractured explained
6.Stop lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning8.9%
436 occurrencesStop lamp not working explained
7.A tyre cords visible or damaged8.1%
397 occurrencesTyre ply or cord exposed, or the casing separating explained
8.A brake lining or pad worn below 1.5mm7.3%
357 occurrencesBrake drum or shoe worn or contaminated explained
9.Exhaust system leaking or insecure7.1%
347 occurrencesExhaust leaking or insecure explained
10.A tyre seriously damaged6.8%
334 occurrencesTyre damaged or deteriorated explained

Warnings without a failure

Most common advisories

Share of all Smart (mcc) Forfour tests carrying each advisory. The denominator differs from the failure list above because an advisory can be issued on a car that passed.

1.Tyre tread depth not in accordance with the requirements26.4%
5,867 testsTyre worn close to the legal limit explained
2.A tyre seriously damaged16.0%
3,563 testsTyre damaged or deteriorated explained
3.Brake disc or drum excessively weakened, insecure or fractured14.1%
3,133 testsBrake disc worn, pitted or scored explained
4.A brake lining or pad worn below 1.5mm6.3%
1,398 testsBrake drum or shoe worn or contaminated explained
5.Brake disc or drum significantly and obviously worn5.1%
1,129 testsBrake disc worn, pitted or scored explained
6.A suspension pin, bush or joint excessively worn3.6%
793 testsSuspension arm bush worn explained
7.Tyre tread depth not in accordance with the requirements3.4%
766 testsTyre worn close to the legal limit explained
8.Fluid leaking excessively and likely to harm the environment or to pose a safety risk to other road users2.4%
542 tests

How wear changes the picture

Pass rate by vehicle age

6–8 yrs78%

9–11 yrs68%

15+ yrs56%

Bands holding too few tests to be meaningful are omitted rather than shown as a rate.

What gets tested

The Forfour fleet

Average mileage recorded at test: 48,188
Fuel mix of tested cars: Petrol97.4%
Electric1.8%
Diesel0.8%

Trim names grouped into this model (2)

Recorded exactly as DVSA holds them. Trim-level names are rolled up so one model is not split across a dozen thin pages.

FORFOUR PASSION
FORFOUR PRIME

Check a specific Smart (mcc) Forfour

A model average tells you the pattern. Its own MOT record tells you the car.

Compare within the range

Other Smart (mcc) models

Smart (mcc) Fortwo — 68.0% adjusted
Smart (mcc) City — 60.1% unadjusted
Smart (mcc) Roadster — 74.1% unadjusted
Smart (mcc) Cabriolet — 63.6% unadjusted
All Smart (mcc) models

Similar test volumes

Compare against other makes

Jaguar XJ — 79.9% adjusted, ranked 57
Mini John Cooper Works — 83.8% adjusted, ranked 27
Mercedes-Benz CLS — 76.4% adjusted, ranked 93
BMW 6 Series — 81.4% adjusted, ranked 46

Common questions

Is the Smart (mcc) Forfour reliable?: On MOT evidence the Smart (mcc) Forfour is well below average. It passes 64.8% of tests once age and mileage are accounted for, against a national average of 72.3%. That figure covers 64% of the national age and mileage range, which is enough to quote but not to rank. This measures how often the car meets the MOT standard, not how often it breaks down or what a repair costs.
What is the most common MOT failure on a Smart (mcc) Forfour?: The item recorded most often is "Tyre tread depth not in accordance with the requirements", which appears in 19.2% of failed Smart (mcc) Forfour tests. Because one failed test can list several items, these shares do not add up to 100%.
What do testers most often warn about on a Smart (mcc) Forfour?: The most common advisory is "Tyre tread depth not in accordance with the requirements", noted on 26.4% of all Smart (mcc) Forfour tests. An advisory is not a failure: it flags something that will likely need attention before the next test.
What mileage does a Smart (mcc) Forfour usually have at its MOT?: The average odometer reading recorded at test is 48,188 miles. This is the mileage across all tested examples of every age, not an annual figure, so treat it as a description of the fleet rather than a target for one car.
Does a Smart (mcc) Forfour get harder to pass as it ages?: Yes. At 6 to 8 years old, 78.1% of Smart (mcc) Forfour tests pass. By fifteen years or more, that falls to 56.5%. Nearly every model follows this pattern, which is why comparing raw pass rates between models is misleading unless age is accounted for.
Are most Smart (mcc) Forfour models petrol or diesel?: Of the Smart (mcc) Forfour cars tested, 97% are petrol, 2% are electric, 1% are diesel. Fuel type affects which items tend to fail, particularly emissions and exhaust components.

How this was worked out

Method and limits

Figures come from the DVSA anonymised MOT testing dataset, published under the Open Government Licence. Only class 4 initial tests are counted: retests are excluded so a car appears once, and abandoned tests are excluded entirely. The adjusted rate is directly standardised across twenty-five age and mileage bands and reweighted onto the national distribution, so this model is compared against cars that have lived a similar life rather than against a younger or lighter-used fleet.

An MOT measures whether a car met a legal standard on the day. It is not a breakdown record, a service history or a running-cost estimate, and a pass rate is a property of a fleet rather than a prediction about one car.