Smart Fortwo II (451) (2007 – 2014)

Reliability score : 5.8/10

The second-generation Smart Fortwo (Type 451) was launched in 2007 to succeed the pioneering 450. Longer by 19 cm to meet crash-test standards (particularly American ones) and improve comfort, it retains its famous exposed Tridion safety cell. Mechanically, it abandons the fragile Mercedes turbocharged engines of the previous generation in favor of naturally aspirated and turbocharged 1.0L 3-cylinder blocks of Mitsubishi origin (3B2 family). While the engine itself is robust, this generation is plagued by two major flaws: a slow Softouch (Getrag) automated gearbox prone to actuator failures, and above all the mhd (Micro Hybrid Drive - Stop&Start) system, whose faulty design can lead to outright engine failure. Official statistics (TÜV, ADAC, What Car?) rank it among the least reliable vehi

✅ Strengths

Unbeatable compactness (2.69 m) and exceptional turning radius
Mitsubishi petrol engines (excluding mhd) inherently very robust (chain-driven)
Astonishing passive safety for its size (Tridion cell)
1.0 Turbo (84 hp) version very versatile and free from the mhd flaw
Low depreciation, high demand in the urban used market

⚠️ Weaknesses

Softouch automated gearbox: exasperating slowness, jerkiness, and frequent actuator failures
Disastrous reliability of the mhd system (engine failure due to belt breakage/overheating)
Very high TÜV defect rate at 3 years: 21.5% (among the worst in the segment)
Very firm comfort (stiff suspension) and poor soundproofing
Cost of maintenance and spare parts (Mercedes-Benz network)

🎯 Verdict

The Smart Fortwo II (451) is a vehicle of contrasts. While its format makes it irreplaceable in the city center, its overall reliability record is poor, penalized by an ADAC breakdown rate of 4.1/1000 and a What Car? score of 2/5 (35% breakdown rate over 12 months). The automated gearbox is a constant source of frustration, both for its drivability and its fragility. The absolute critical point is the 1.0 mhd (71 hp) engine: its poorly designed Stop&Start system leads to fatal belt breakages for the engine. Buying advice: Flee from the mhd versions unless the seller provides recent invoices proving the complete update of the system (shims, shaft, reinforced belt). Unhesitatingly favor the 84 hp 1.0 Turbo version (which does not have the mhd system) or the very first 71 hp models from 2007/early 2008 (before the introduction of the mhd).

Common issues

Défaillance de l'actionneur d'embrayage (ou de boîte de vitesses) Medium

🔧 60 000 – 120 000 km

💶 250 – 500 €

Vérifier la fluidité des passages de vitesses et l'absence de bruits anormaux.

Dysfonctionnement de l'unité SAM (Signal Acquisition Module) High

🔧 80 000 – 150 000 km

💶 600 – 1 200 €

Tester toutes les fonctions électriques (phares, essuie-glaces, démarrage) avant achat.

Défaillance du turbocompresseur (modèles turbo essence) High

🔧 100 000 – 180 000 km

💶 900 – 1 800 €

Écouter les sifflements excessifs, vérifier la fumée bleue à l'échappement.

Usure des supports moteur Medium

🔧 80 000 – 150 000 km

💶 200 – 450 €

Observer les vibrations excessives au ralenti ou lors des accélérations.

Estimated maintenance costs

Oil change	£60 – 120
Clutch	£650 – 1 200
Complete brakes	£200 – 450
Estimated annual budget	£500 – 1 000

Indicative estimates (independent garage, UK market). Prices vary by region and year.