Smart ForFour
The Renault three-cylinder turbo (identical to the Renault Twingo III unit) is the best engine Smart has ever fitted. Punchy, economical and reliable. The Brabus version (80 kW) adds even more driving fun. The clear recommendation for the Smart 453.
Little firecracker
109 hp Brabus ForFour — ESP cannot be deactivated, but the rear still shows character. Best ForFour 453 variant for driving fun with four seats.
Engine Weaknesses 4
The known wastegate fault also affects the facelifted H4B. Moisture in the plastic housing destroys the electronics and crown gear. Renault has offered the wastegate as a separate spare part from 2020.
Symptoms: Yellow engine warning light, power loss, no boost pressure, limp mode
The DCT gearbox in the Smart 453 shifts at high revs, which reduces comfort. In stop-and-go traffic the clutch slips continuously in 2nd gear.
Symptoms: Harsh shifting, juddering on pull-away, clutch smell, delayed engagement, gearbox fault message
Isolated cases of coolant loss at hose connections. In the Smart with the engine at the rear and the radiator at the front, the coolant lines run the full length of the underfloor.
Symptoms: Dropping coolant level, coolant warning light, damp patches on hoses, steam from a hot engine
The lambda sensor can fail at low mileage. Affected vehicles fail the emissions test; fault code points to a defective sensor heater element.
Symptoms: Engine warning light, failed emissions test, increased fuel consumption, rough engine running
Vehicle Weaknesses 11
The ForFour 453 steering rack can fail at very low mileage (reports from as little as 8,000 km). The typical cause is worn carbon brushes in the electric power steering motor. Complete steering rack replacement required.
The 6-speed dual-clutch gearbox (twinamic) judders and lurches when pulling away in city traffic, especially in cold conditions. Identical issue to the ForTwo 453. Software updates only provide temporary relief; at severe wear, repair including fitting costs approx. €3,500.
The rear shock absorbers of the ForFour 453 wear faster than expected. Rubber boots on the springs become porous and crack. Specialists criticize the rear axle suspension as not particularly robust. Typical issue from the second MOT onwards.
The rear brake drums rust heavily on low-mileage vehicles and after extended standing periods. Surface rust often cannot be fully cleared by braking and can adhere permanently. Particularly problematic on short-trip city vehicles.
Like the ForTwo 453, early production years were delivered with weak batteries. The small engine and numerous electrical consumers put a heavy load on the battery. Regular checks are necessary, especially before winter.
Identical problem to the ForTwo 453: the touchscreen freezes and does not respond to input. Fix: pull fuse no. 26 (yellow, 20 A) in the glove box for one minute. A software update at the dealer provides a lasting remedy.
The tailgate gas struts lose pressure over time and no longer hold the hatch open. The tailgate drops on your head while loading. Cheap replacement parts (from €10) are easy to swap yourself.
The rear seat backrests can break or the fold/cargo mechanism locking fails. A known weakness documented in forums and review portals. Replacement or repair at a workshop required.
Short-trip use means condensation water in the exhaust system never dries out. The silencer and connecting pipe rust from the inside and outside. Replacement required; parts are costly. Typical problem after approx. 80,000 km or 8 years.
Bacteria and mould on the AC evaporator cause a musty smell when the air conditioning is switched on. Occurs particularly when the AC is rarely used or not allowed to dry out after use. Disinfection or evaporator cleaning helps.
Poorly fitted plastic trim panels inside the ForFour 453 generate creaking and rattling noises. The underbody cover and door panels are particularly affected. Some noises are difficult to locate in the workshop.