Smart ForFour 453-FL
Weaknesses, engine ratings and buying advice
The Smart EQ ForFour (2017–2024) is the fully electric version of the ForFour 453, powered by a 60 kW motor with 160 Nm. WLTP range: 159 km officially — real-world is 90–120 km under normal conditions, less in winter. This is unambiguously a short-range city commuter.
Electrical system: The 12V lead-acid battery is the biggest everyday headache. Leave the car unused and it drains — the stock Fiamm unit is described as an 'absolute weak point' across the EQ community. Swapping it for an AGM battery (e.g. Varta A8 AGM, €80–120) fixes the problem permanently. The DC-DC converter is rarer but more expensive: a failure means the car won't start. Diagnosis: measure 12V voltage in Ready mode — below 13V suspects the converter. Repair: €2,400–5,000 depending on workshop. From late 2025, spare parts are available individually from Mercedes.
Charging: Charging aborts after a few minutes do occur, often caused by wallbox grid noise or a depleted 12V battery. The EQ ForFour charges at up to 22 kW AC — no DC fast charging.
Heating: The PTC heater delivers barely any warmth in the first few minutes in winter. This is partly a software-enforced delay (WLTP range optimisation) and partly flap calibration needing a reset. Seat heating is the practical workaround.
Recall: Rear axle mounting bolts under-torqued (2022 build year, KBA 012337). Very limited number of cars — workshop visit takes 20–30 minutes.
Test-drive checklist: Have 12V voltage checked (takes 2 minutes). Test charging: plug in, wait 5 minutes, does it abort? Test heating with a cold vehicle. Check Smart Control app connectivity.
2026 market: Smart EQ ForFour from €10,000 (older examples). 2020–2022 builds from €14,000–18,000. Best buy: 2020–2021 example with AGM battery already fitted, recall checked, under 40,000 km — the EQ ForFour is ideal for city commuting, but buy with realistic range expectations.
Generations
Engine Overview
The Smart ForFour 453-FL is available with one engine variant at 75 hp.
Electric variants of the ForTwo and ForFour. Various battery sizes depending on generation and facelift.
No known weaknesses documented.
Vehicle Weaknesses
| Weakness | Cost | |
|---|---|---|
| DC-DC Converter Failure — Vehicle Does Not Start A faulty DC-DC converter prevents the 12V battery from charging, causing the HV contactors not to close. Repair requires 8–16 hours of labour due to difficult accessibility. Symptoms: Fault message 'malfunction – visit workshop', vehicle cannot be driven, 12V voltage below 13 V from 70,000 km | High | |
| 12V Battery Drains Quickly Like the ForTwo: the 12V lead-acid battery is not designed for BEV operation and sulphates. After 3–4 years a complete failure that renders the vehicle undriveable is to be expected. Symptoms: Yellow battery warning light, vehicle does not start, especially pronounced in cold below 0 °C from 40,000 km | Low | |
| Charging Aborts at Wallboxes Charging process aborts after 40 seconds to a few minutes. Red battery symbol appears on the dashboard. The on-board charger is sensitive to mains interference. Symptoms: Charge cable LED flashes red, error message on instrument cluster, self-resolving after vehicle restart from 30,000 km | Low | |
| Smart Control App — Unreliable Connection The official app regularly loses the vehicle connection. Pre-conditioning via app starts reliably in only about 50% of cases, which limits the main comfort advantage of the EQ. Symptoms: App shows vehicle offline, climate command not executed, daily re-login required | Low |
Test Reports
AUTO BILD TÜV-Report 2025
The facelifted ForFour 453 shares the ForTwo's MOT weaknesses: lighting faults, occasional oil seepage on older examples and handbrake issues. Suspension components and driveshafts remain unproblematic.
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Known Problems and Issues +
A total of 6 weaknesses have been documented for the Smart ForFour 453-FL (2020–2024). Typical issues affect Electronics, HVAC, Other.
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 453-FL have? +
What should I look for when buying a used Smart ForFour 453-FL? +
Which engine is recommended? +
Which Smart ForFour 453-FL engine is the most fun? +
Is the Smart ForFour 453-FL worth buying used? +
What horsepower variants are available for the Smart ForFour 453-FL? +
Last updated: February 2026 · All information without guarantee