Smart ForFour 454
Weaknesses, engine ratings and buying advice
109–177 PS
1.5L Benzin
Nippy four-seater
Fun to Drive!95 PS
1.3L Benzin
4 weaknesses
Good Choice109–177 PS
1.5L Benzin
4 weaknesses
Stay Away!Generations
Engine Overview
The Smart ForFour 454 is available with 4 engine variants — from 64 to 177 hp. 3 variants had engine changes — the model year is crucial.
The Smart 1.5L CDI Turbo (Diesel, 68–95 PS) comes with 2 different engines: OM639 (2004–2006, Be Careful) und OM639 (2004–2006, Be Careful). Pay attention to the model year for the 1.5L CDI Turbo!
The Smart 1.1L (Benziner, 64–75 PS) comes with 2 different engines: 3A91 (2004–2006, Be Careful) und 3A91 (2004–2006, Be Careful). Pay attention to the model year for the 1.1L!
The Smart 1.3L (Benziner, 95 PS) has the 4A90 (1.3L) — rated: "Good Choice", 4 known weaknesses.
The Smart 1.5L (Benziner, 109–177 PS) comes with 2 different engines: 4A91 (2004–2006, Stay Away!) und 4A91 (2005–2006, Stay Away!). Pay attention to the model year for the 1.5L!
Vehicle Weaknesses
| Weakness | Cost | |
|---|---|---|
| Sills and Wheel Arches Rust The sills and wheel arch edges of the ForFour 454 are regularly affected by rust on older vehicles, as stone chips and moisture attack quickly. Frequent city use and lack of underbody maintenance accelerate the problem. Symptoms: Rust bubbles on sills and wheel arch edges, visible rust-through, paint flaking from 90,000 km | Medium | |
| Exhaust System Corrodes The ForFour 454 exhaust system rusts primarily at the rear silencer due to typical short-trip city use. Condensation water collects in the silencer and corrodes the steel from the inside. A complete replacement can be due before 80,000 km. Symptoms: Visible rust on the rear silencer, holes in the silencer, increased noise, rattling from 70,000 km | Low |
Alternatives
Smart ForFour 453
Nachfolger (2014–2022)
Mitsubishi Colt Z30
Kleinwagen (2004–2012)
Fiat Panda 169
Kleinwagen (2003–2012)
Nissan Micra K12
Kleinwagen (2003–2010)
Honda Jazz GD
Kleinwagen (2002–2008)
Hyundai Getz TB
Kleinwagen (2002–2009)
MINI MINI R53
Kleinwagen (2002–2006)
Known Problems and Issues
A total of 22 weaknesses have been documented for the Smart ForFour 454 (2004–2006) — 12 engine-related and 10 vehicle-related. One problem engine: 4A91 (1.5L). Typical issues affect Rust, Suspension, Electronics, Steering. Considered reliable: 4A90 (1.3L).
ForFour (3A91, 2004–2006) — Be Careful: Timing chain stretched, Valve clearance drifts out of spec, Clutch actuator and premature clutch wear. Power: 64 PS.
ForFour (3A91, 2004–2006) — Be Careful: Timing chain stretched, Valve clearance drifts out of spec, Clutch actuator and premature clutch wear. Power: 75 PS.
ForFour (4A91, 2004–2006) — Stay Away!: Wastegate actuator faulty — moisture destroys crown gear, Turbocharger total failure at just 20,000 km, Twinamic dual clutch wears — harsh shifting and judder. Power: 109 PS.
ForFour (4A91, 2005–2006) — Stay Away!: Wastegate actuator faulty — moisture destroys crown gear, Turbocharger total failure at just 20,000 km, Twinamic dual clutch wears — harsh shifting and judder. Power: 177 PS.
What to watch out for with the Smart ForFour? See the detailed listing of all engine and vehicle weaknesses in the sections above.
Frequently Asked Questions
What problems and weaknesses does the Smart ForFour 454 have? +
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Last updated: February 2026 · All information without guarantee