Fault File
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Smart Forfour

All generations and engines together · 21,187 MOT tests in the 2025 data · typical mileage at age 7: 40k

First-time failure at age 7
22.4%
Across 4,039 tests. The average across all tracked models is 19.5%.
Rank at age 7
177 of 239
1 = lowest failure rate among the models tracked.
Typical mileage at age 7
40k miles
Check the mileage view below; low-mileage models can look better by age than they are.

Generation

Split by first-registration year. Cars registered in a changeover year can belong to either generation.

How this model wears

Smart ForfourClass average, all tracked models

Known issues

Measured

Computed from DVSA MOT results, all of Great Britain, 2025. Nothing here is opinion.

What testers flag

Share of tests where each item was recorded. The dark tick is the class average across all tracked models; bars are scaled within each group.

Faults with the car itself

The rows that judge the model rather than its keeper. 17,685 tests in this band.

A suspension pin, bush or joint excessively worn
Advisory
4.8%class 6.7%
A suspension pin, bush or joint excessively worn
Fail
3.3%class 0.7%
Stop lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning
Fail
3.0%class 0.8%
Lambda coefficient outside the default limits or the range specified by the manufacturer
Fail
2.9%class 0.2%
Fluid leaking excessively and likely to harm the environment or to pose a safety risk to other road users
Advisory
2.0%class 2.0%
Engine MIL illuminated indicating a malfunction
Fail
1.8%class 0.5%
Exhaust system leaking or insecure
Advisory
1.7%class 0.6%
A spring or spring component fractured or seriously weakened
Fail
1.7%class 1.4%
Lamp emitted colour, position or intensity not in accordance with the requirements
Advisory
1.7%class 0.3%
Exhaust system leaking or insecure
Fail
1.5%class 0.2%

Wear, upkeep and luck

Tyres, pads and stone chips say more about how the car was driven and maintained than about how it was built.

Tyre tread depth not in accordance with the requirements
Advisory
30.5%class 22.9%
A tyre seriously damaged
Advisory
17.4%class 12.7%
Brake disc or drum excessively weakened, insecure or fractured
Advisory
13.4%class 10.1%
A brake lining or pad worn below 1.5mm
Advisory
6.1%class 8.7%
Brake disc or drum significantly and obviously worn
Advisory
5.1%class 3.4%
Tyre tread depth not in accordance with the requirements
Fail
4.4%class 2.2%
Wiper blade missing or obviously not clearing the windscreen
Fail
3.3%class 1.7%
Windscreen washers not working or not providing sufficient fluid to clear the windscreen
Fail
2.0%class 0.8%

Unconfirmed issues

Reported

Owner folklore from forums and the motoring press. Most of it never shows up in an MOT, which is why this section exists at all.

Turbo actuator failure on the 0.9 turbo petrol

Emerging

Owners of the 0.9-litre turbo (90 TCe) engine have reported the turbo actuator failing from as little as 5,000 miles, with loss of power and warning lights. Honest John's reader reports mention a knock-on problem too: a parts shortage for this turbo left some owners waiting weeks for a fix. It is not clear how widespread this is against the number of 0.9 turbo cars on the road, so treat it as a pattern to check for rather than a certainty.

Reported from 5,000 miles · sources: Honest John reader reports, Auto Express reliability review

Twin-clutch auto: sticking clutch and denied warranty claims

Twinamic auto only

On the automated-clutch Twinamic gearbox, owners report the clutch sticking down or the car refusing to select gear, sometimes from new. In at least one Honest John case Smart refused a warranty claim at 19,000 miles, calling it wear and tear rather than a defect, which left the owner paying for the repair. Manual cars do not have this gearbox and are not affected.

Reported from new to ~20k miles · sources: Honest John reader reports

Touchscreen and infotainment glitches

Partly in the MOT data

Owners report the touchscreen freezing or going unresponsive, and separately the navigation losing its SD card after a software update, in one case leading to a dealer suggesting a full wiring loom replacement. This is the folklore cousin of the measured 'lights & electrics' fault for this class: the wiring and electronics niggles owners describe day to day are a different symptom to what an MOT tester flags, but they point at the same underlying weak spot in the car's electrics.

Reported on later (2018+) cars · sources: Honest John reader reports

Early Softouch automated-manual gearbox faults (2004-2006 cars)

Confirmed pattern

On the original Forfour's Softouch semi-automatic, the gear actuator is a well-documented weak point: it can wear out and leave the car stuck in gear, or cause it to hop and jump between gears at idle or crawling speed. Some cases needed the ECU replaced as well as the actuator once things went wrong. This is old enough now that most surviving cars will have already had the actuator done at least once, but ask.

Reported from an early age, worsening with mileage · sources: Honest John reader reports (multiple)

General brand reliability below class average

Disputed

Smart as a brand has a poor track record in owner satisfaction surveys compared with rivals like Hyundai and Toyota, and reviewers note the small three-cylinder engines feel strained and noisy at motorway speeds, which some owners read as a sign of stress on the engine rather than just cabin noise. Whether that noise translates into actual long-term wear is disputed, plenty of owners report no problems at all past 100k miles.

General, not tied to one mileage · sources: Auto Express reliability review, Honest John

Viewing one? Ask this

Built from the two sections above.

Start the car from cold and pull away, watching for hesitation or hopping. On automated-clutch (Twinamic) cars this can mean the clutch actuator is on its way out.
Push the car hard up an incline or check for a warning light under load. Loss of power or a limp mode points at the 0.9 turbo actuator fault.
Prod every button on the touchscreen and try the sat nav if fitted. A frozen screen or nav that won't read its SD card is a known niggle, and a fix can mean rewiring work.
On a 2004-2006 Softouch semi-auto, try slow manoeuvring in a car park. Jumping or hopping between gears at low speed means the actuator is worn or failing.
Check the service history for any gearbox actuator or ECU replacement. Its absence on an older Softouch car is not necessarily good news, it may just mean the fault hasn't shown up yet.
Ask to see a recent MOT certificate, not just the pass/fail. Look for lighting or electrical advisories, they are the measured version of this car's electrical niggles.
Ask how long the current owner has had it and why they're selling. A car sold soon after a warranty repair was refused is a red flag worth probing.

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