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Smart Forfour reliability

E · Poor

MOT pass rates and common problems from 181,658 MOT tests of cars first registered 2004–2019.

Jump to: YearsEnginesCommon failures
74.0%pass first time
−5.0 ptsvs typical car
Beats 15%of cars
181,658MOT tests

Verdict

The Smart Forfour passes its MOT first time on 74.0% of tests, 5.0 points lower than a typical car of the same age and mileage (78.9%). That puts it ahead of 15% of cars on UK roads once age and mileage are taken into account.

By year of first registration, the 2018 Forfour does best (beats 7% of cars) and the 2017 worst (beats 6%).

Of its engines, the 0.9 Petrol does best (beats 6%) and the 1.0 Petrol worst (beats 6%).

Better than average on steering.

Watch these weak spots

Tyres1.4×as often as a typical car
Visibility1.6×as often as a typical car
Windscreen wipers1.8×as often as a typical car
Exhaust emissions (catalyst)3.9×as often as a typical car

MOT pass rate by age

First-time pass rate at each MOT by the car’s age in years.

50%60%70%80%90%100%3456789101112131415161718192086%81%76%70%66%57%55%57%56%
Smart ForfourTypical car, same age & mileage

Best and worst years

By year of first registration, ranked against all cars on UK roads after adjusting for age and mileage. Green = better than half of cars.

2004
Beats 47%
2005
Beats 56%
2006
Beats 54%
2015
Beats 6%
2016
Beats 6%
2017
Beats 6%
2018
Beats 7%
2019
Beats 6%

Engines

All years, most common first. Grades compare each car with cars of the same age and mileage (A = best 20% of cars on UK roads, E = worst 20%), so an older or higher-mileage car can grade above one with a higher pass rate.

EngineYearsTestsPass rateRankGrade
1.0 Petrol2015–201998,11677.2%Beats 6%E
0.9 Petrol2015–201952,78078.2%Beats 6%E
1.1 Petrol2004–200614,85455.6%Beats 51%C
1.3 Petrol2004–20068,19157.5%Beats 54%C
1.5 Petrol2005–20064,23260.1%Beats 64%B
1.5 Diesel2005–20063,48553.4%Beats 48%C

Where it fails

Each area compared with a typical car of the same age and mileage, in points of pass rate. Tap or hover an area to see what to check.

Exhaust: 3.7% of tests fail on emissions & leaks, against 1.9% for a typical car of the same age and mileage. Listen for a blowing exhaust at start-up and look underneath for oil or fluid leaks.Suspension: 5.4% of tests fail on suspension, against 5.4% for a typical car of the same age and mileage. Listen for knocks over speed bumps and push each corner down: it should settle at once.Lights: 8.9% of tests fail on lights & electrics, against 7.2% for a typical car of the same age and mileage. Walk round the car with every light on, including brake, fog and number plate lights.Tyres: 7.1% of tests fail on tyres, against 5.2% for a typical car of the same age and mileage. Check the tread on every tyre, including the inner edge, and look for cuts or bulges.Brakes: 4.5% of tests fail on brakes, against 4.6% for a typical car of the same age and mileage. Brake firmly on the test drive: the car should stop straight with no pulsing or grinding.Lights: 8.9% of tests fail on lights & electrics, against 7.2% for a typical car of the same age and mileage. Walk round the car with every light on, including brake, fog and number plate lights.Lights−1.7 ptsTyres: 7.1% of tests fail on tyres, against 5.2% for a typical car of the same age and mileage. Check the tread on every tyre, including the inner edge, and look for cuts or bulges.Tyres−1.9 ptsBrakes: 4.5% of tests fail on brakes, against 4.6% for a typical car of the same age and mileage. Brake firmly on the test drive: the car should stop straight with no pulsing or grinding.Brakes+0.1 ptsSuspension: 5.4% of tests fail on suspension, against 5.4% for a typical car of the same age and mileage. Listen for knocks over speed bumps and push each corner down: it should settle at once.Suspension−0.1 ptsExhaust: 3.7% of tests fail on emissions & leaks, against 1.9% for a typical car of the same age and mileage. Listen for a blowing exhaust at start-up and look underneath for oil or fluid leaks.Exhaust−1.7 ptsSuspension: 5.4% of tests fail on suspension, against 5.4% for a typical car of the same age and mileage. Listen for knocks over speed bumps and push each corner down: it should settle at once.Brakes: 4.5% of tests fail on brakes, against 4.6% for a typical car of the same age and mileage. Brake firmly on the test drive: the car should stop straight with no pulsing or grinding.Tyres: 7.1% of tests fail on tyres, against 5.2% for a typical car of the same age and mileage. Check the tread on every tyre, including the inner edge, and look for cuts or bulges.Lights: 8.9% of tests fail on lights & electrics, against 7.2% for a typical car of the same age and mileage. Walk round the car with every light on, including brake, fog and number plate lights.Exhaust: 3.7% of tests fail on emissions & leaks, against 1.9% for a typical car of the same age and mileage. Listen for a blowing exhaust at start-up and look underneath for oil or fluid leaks.Lights: 8.9% of tests fail on lights & electrics, against 7.2% for a typical car of the same age and mileage. Walk round the car with every light on, including brake, fog and number plate lights.Lights−1.7 ptsTyres: 7.1% of tests fail on tyres, against 5.2% for a typical car of the same age and mileage. Check the tread on every tyre, including the inner edge, and look for cuts or bulges.Tyres−1.9 ptsBrakes: 4.5% of tests fail on brakes, against 4.6% for a typical car of the same age and mileage. Brake firmly on the test drive: the car should stop straight with no pulsing or grinding.Brakes+0.1 ptsSuspension: 5.4% of tests fail on suspension, against 5.4% for a typical car of the same age and mileage. Listen for knocks over speed bumps and push each corner down: it should settle at once.Suspension−0.1 ptsExhaust: 3.7% of tests fail on emissions & leaks, against 1.9% for a typical car of the same age and mileage. Listen for a blowing exhaust at start-up and look underneath for oil or fluid leaks.Exhaust−1.7 pts
Better than typicalTypicalWorse than typical
Tyres: 7.1% of tests fail on tyres, against 5.2% for a typical car of the same age and mileage. Check the tread on every tyre, including the inner edge, and look for cuts or bulges.

Every MOT area

Share of tests failing on each area, against a typical car of the same age and mileage (black line).

Lights & electrics
8.9% vs 7.2%
Tyres
7.1% vs 5.2%
Visibility
6.6% vs 4.0%
Suspension
5.4% vs 5.4%
Brakes
4.5% vs 4.6%
Emissions & leaks
3.7% vs 1.9%
Body & structure
2.2% vs 2.0%
Steering
0.8% vs 1.1%
Seat belts & airbags
0.4% vs 0.7%
Wheels
0.2% vs 0.2%

Buying one or MOT due? Check these

  • Windscreen wipers 1.8× typical
    Test the washers and wipers: a cheap fix, but a very common MOT fail.
  • Exhaust emissions (catalyst) 3.9× typical
    Check past MOT emissions readings in the car's history: rising readings can mean catalyst or sensor problems.
  • Brake lights 2.2× typical
    Walk around with the lights on: bulb failures are the easiest MOT fails to avoid.
  • Tyre tread depth 1.7× typical
    Check every tyre, including the inner edge, has at least 3 mm of tread. Uneven wear can point to alignment or suspension problems.
  • Suspension ball joints 2.4× typical
    Listen for knocks over speed bumps and feel for wandering or vague steering.
  • Brake discs 1.8× typical
    Look through the wheel spokes for scored discs or a heavy rust lip on the edge.

Pass rate by mileage

First-time pass rate by mileage at the test.

40%60%80%100%0k10k20k30k40k50k60k70k80k90k100k110k120k130k92%81%72%64%57%53%52%
Smart ForfourTypical car

Most common MOT failures

ItemThis carTypicalvs typical
Windscreen wipers4.2%2.3%1.8×
Tyre damage & cracking3.5%3.0%1.2×
Tyre tread depth3.0%1.8%1.7×
Brake lights2.9%1.3%2.2×
Headlight aim2.7%2.3%1.2×
Windscreen washers2.3%1.6%1.5×
Exhaust emissions (catalyst)2.2%0.6%3.9×
Brake pads1.9%1.5%1.3×
Suspension ball joints1.9%0.8%2.4×
Headlight bulbs & units1.5%1.3%1.2×

Specific defects found

Tester wording for the most frequent failure items, per 1,000 tests.

Defectper 1,000
Wiper blade missing or obviously not clearing the windscreen41.2
Tyre tread depth not in accordance with the requirements30.0
A suspension pin, bush or joint excessively worn28.3
Stop lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning27.1
The aim of a headlamp is not within limits laid down in the requirements27.0
Windscreen washers not working or not providing sufficient fluid to clear the windscreen22.9
A tyre seriously damaged20.0
A brake lining or pad worn below 1.5mm18.3
Check another car

Pick a make and model to see its MOT pass rate, best and worst years and weak spots.

Every year and engine

Tap a year to see its engines. Grades compare each car with cars of the same age and mileage (A = best 20% of cars on UK roads, E = worst 20%), so an older or higher-mileage car can grade above one with a higher pass rate.

2019 Smart Forfour2 engines83.4% passE
EngineTestsPass rateRankGrade
1.0 Petrol5,11382.9%Beats 6%E
0.9 Petrol3,74384.2%Beats 8%E
2018 Smart Forfour2 engines82.1% passE
EngineTestsPass rateRankGrade
1.0 Petrol13,59281.9%Beats 8%E
0.9 Petrol7,78282.5%Beats 6%E
2017 Smart Forfour2 engines79.2% passE
EngineTestsPass rateRankGrade
1.0 Petrol20,61678.2%Beats 5%E
0.9 Petrol11,24780.9%Beats 8%E
2016 Smart Forfour2 engines76.8% passE
EngineTestsPass rateRankGrade
1.0 Petrol25,87876.6%Beats 6%E
0.9 Petrol14,86077.0%Beats 6%E
2015 Smart Forfour2 engines74.0% passE
EngineTestsPass rateRankGrade
1.0 Petrol32,91774.2%Beats 6%E
0.9 Petrol15,14873.7%Beats 5%E
2006 Smart Forfour4 engines57.5% passC
EngineTestsPass rateRankGrade
1.1 Petrol6,40257.2%Beats 53%C
1.3 Petrol2,47159.1%Beats 57%C
1.5 Petrol2,05059.4%Beats 60%C
1.5 Diesel1,38852.9%Beats 42%C
2005 Smart Forfour4 engines56.6% passC
EngineTestsPass rateRankGrade
1.1 Petrol5,80855.2%Beats 51%C
1.3 Petrol4,38857.6%Beats 55%C
1.5 Petrol2,18260.7%Beats 68%B
1.5 Diesel2,09753.7%Beats 51%C
2004 Smart Forfour2 engines53.1% passC
EngineTestsPass rateRankGrade
1.1 Petrol2,64452.5%Beats 48%C
1.3 Petrol1,33254.1%Beats 45%C

FAQ

What is the Smart Forfour MOT pass rate?

74.0% of MOT tests on the Smart Forfour were passed first time, based on 181,658 tests between 2018 and 2026 of cars first registered 2004–2019. A typical car of the same age and mileage passes 78.9% of the time.

Is the Smart Forfour reliable?

On MOT results it rates E (poor): it passes first time less often than a typical car of the same age and mileage and does better than 15% of cars on UK roads. MOT results cover safety and emissions items, not every kind of breakdown.

Which Smart Forfour year is best?

Among years with enough data, the 2018 Forfour does best for its age and mileage: it beats 7% of cars on UK roads. The 2017 does worst: it beats 6%.

Which Smart Forfour engine is best?

Across all years, the 0.9 Petrol does best: it beats 6% of cars on UK roads. The 1.0 Petrol does worst: it beats 6%.

What are the most common MOT failures on the Smart Forfour?

The most common failure items are windscreen wipers, tyre damage & cracking, tyre tread depth. Compared with similar cars, windscreen wipers comes up 1.8× as often.

How we calculate this. We use official MOT results for cars tested in Great Britain from 2018 to 2026. Each car is compared with typical cars of the same age and mileage, so old and new cars are judged fairly; “pts” are percentage points above or below them. Differences also reflect how cars are used and maintained, not only how they are built.