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Smart · Micro Car · 2007–2014

Smart ForTwo 451

Weaknesses, engine ratings and buying advice

2.3 / 5.0 · Based on 3 engine variants
Most Fun Engine

75–82 PS

Elektromotor Elektro

City runabout without noise

Decent
Problem Engine

41–54 PS

0.8L CDI Diesel

4 weaknesses

Stay Away!

Body Variants

The Smart ForTwo 451 is available as Coupé and Cabrio — choose your body type for specific insurance data:

Generations


Engine Overview

The Smart ForTwo 451 is available with 4 engine variants — from 41 to 102 hp. 2 variants had engine changes — the model year is crucial.

0.8L CDI · Diesel· 41–54 PS Engine Change
2007 2014
Stay Away! 4 weaknesses
2009 2014
Stay Away! 4 weaknesses
1.0L · Benziner· 61–102 PS Engine Change
2007 2014
Be Careful 9 weaknesses
2007 2014
Be Careful 9 weaknesses
2007 2014
Be Careful 9 weaknesses
2007 2014
Be Careful 9 weaknesses
ForTwo ED · Elektro· 75 PS
2012 2014
Be Careful 0 weaknesses
ForTwo ED Brabus · Elektro· 82 PS
2012 2014
Be Careful 0 weaknesses

The Smart 0.8L CDI (Diesel, 41–54 PS) comes with 2 different engines: OM660 (2007–2014, Stay Away!) und OM660 (2009–2014, Stay Away!). Pay attention to the model year for the 0.8L CDI!

The Smart 1.0L (Benziner, 61–102 PS) comes with 4 different engines: 3B21 (2007–2014, Be Careful) und 3B21 (2007–2014, Be Careful) und 3B21 (2007–2014, Be Careful) und 3B21 (2007–2014, Be Careful). Pay attention to the model year for the 1.0L!

The Smart ForTwo ED (Elektro, 75 PS) has the Smart-ED (Elektromotor) — rated: "Be Careful".

The Smart ForTwo ED Brabus (Elektro, 82 PS) has the Smart-ED (Elektromotor) — rated: "Be Careful".

Vehicle Weaknesses

WeaknessCost
Clutch Actuator Defective (3-Bar Fault)

The electric clutch actuator (part no. A4512500062) frequently fails from 80,000–100,000 km. The shaft of the internal electric motor breaks, and gears can no longer be selected. Three dashes on the display, limp mode, or vehicle completely undriveable.

Symptoms: Three dashes/bars on display instead of gear readout, gearbox does not clutch or judders heavily, vehicle in limp mode
from 90,000 km
Medium
Gearbox Shift Actuator Defective

The shift actuator (part no. A4518290201) controls the electronic gear selection. When it fails, individual gears are lost or the gearbox no longer shifts at all. Typical problem on older examples from 100,000 km.

Symptoms: Individual gears cannot be engaged, shifting problems, limp mode, error message on display
from 100,000 km
Medium
NHTSA Owner Complaints
Below Average
269 complaints · 2007–2014
Powertrain
62 ⚠ 3
Engine
61
Electrical
40
Other
36 ⚠ 2
Engine & Cooling
21

Top Reported Issues

Powertrain (62 complaints)
Engine (61 complaints)
Electrical (40 complaints)
Source: NHTSA (nhtsa.gov) · 2026-03

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Known Problems and Issues

A total of 27 weaknesses have been documented for the Smart ForTwo 451 (2007–2014) — 13 engine-related and 14 vehicle-related. One problem engine: OM660 (0.8L CDI). Typical issues affect Gearbox, Rust, Electronics, Steering.

ForTwo (OM660, 2007–2014) — Stay Away!: Turbocharger damage from icing in the intake tract, Injectors coked up or faulty, Diesel particulate filter clogged. Power: 41–45 PS.

ForTwo (OM660, 2009–2014) — Stay Away!: Turbocharger damage from icing in the intake tract, Injectors coked up or faulty, Diesel particulate filter clogged. Power: 54 PS.

ForTwo (3B21, 2007–2014) — Be Careful: Timing chain tensioner and guide wear, Clutch actuator wears out — electric motor shaft shears off, Ignition coil failure — misfires on individual cylinders. Power: 61 PS.

ForTwo (3B21, 2007–2014) — Be Careful: Timing chain tensioner and guide wear, Clutch actuator wears out — electric motor shaft shears off, Ignition coil failure — misfires on individual cylinders. Power: 71 PS.

ForTwo (3B21, 2007–2014) — Be Careful: Timing chain tensioner and guide wear, Clutch actuator wears out — electric motor shaft shears off, Ignition coil failure — misfires on individual cylinders. Power: 84 PS.

ForTwo (3B21, 2007–2014) — Be Careful: Timing chain tensioner and guide wear, Clutch actuator wears out — electric motor shaft shears off, Ignition coil failure — misfires on individual cylinders. Power: 98–102 PS.

What to watch out for with the Smart ForTwo? See the detailed listing of all engine and vehicle weaknesses in the sections above.

Frequently Asked Questions

What problems and weaknesses does the Smart ForTwo 451 have? +
The Smart ForTwo 451 has 13 known engine weaknesses and 14 vehicle weaknesses.
What should I look for when buying a used Smart ForTwo 451? +
faq.watch_a_avoid
Which engine is recommended? +
Be careful: 3B21 (1.0L), Smart-ED (Elektromotor). No engine is rated 'Good Choice'. The most fun to drive is the Smart-ED (Elektromotor). Problem engine: OM660 (0.8L CDI) — stay away!
Which Smart ForTwo 451 engine is the most fun? +
The {code} ({displacement}) offers the most driving fun in the Smart ForTwo 451 — rated: "Decent". {description} Instant torque makes the ED surprisingly brisk in city traffic. 145 km range limits it to city use.
Is the Smart ForTwo 451 worth buying used? +
Caution is advised with the Smart ForTwo 451 — 1 of 3 engine variants are rated 'Stay Away!'. The engine choice is crucial.
What horsepower variants are available for the Smart ForTwo 451? +
The Smart ForTwo 451 is available with engine variants from 41 to 102 hp. Petrol: 3B21 (1.0L). Diesel: OM660 (0.8L CDI).

Last updated: February 2026 · All information without guarantee