2017–2024 Smart Fortwo Electric Drive / EQ (453)

Downloads & resources

The manuals, diagrams, and quick references that ship with this chassis. PDFs open in a new tab; on-site pages are owner-to-owner walkthroughs.

Missing a manual you'd expect to see? Email us — if it exists, we'll add it.

The first 30 days

If you just bought a Fortwo Electric Drive / EQ (453), this is the order to do things in. Stay ahead of these and you'll save yourself a lot of money.

1. Verify real range, not the sticker

   Charge to 100% on your home charger. Drive a representative loop — your normal commute, your normal speeds, your normal climate. Note the indicated range when full and the indicated range when you finish. The number you should care about is the real one on your car today, not the EPA 58-mile figure from 2017. Phoenix-area cars and any car that lived hot will be on the lower end. If the car arrives at your charger every night with 30+ miles still showing on a 25-mile commute, you're fine. If it doesn't, this is not the car for you and you need to know that in week one.

2. Test the 12V auxiliary battery before you trust it

   The EQ has a 12V AGM aux battery — yes, the electric car has one too. It powers the SAM, central locking, and the contactor that engages the high-voltage pack. When it dies, the high-voltage system won't engage and the car simply won't 'start' even with a fully-charged main battery. This is the single most-Googled EV-Smart problem. Symptoms: intermittent no-start, weird module errors on cold mornings, dash warnings that clear on a jump. If your aux battery is 4+ years old, replace it now. See [Auxiliary 12V Battery (453)](/maintenance/auxiliary-battery-453/).

3. Confirm your home charging works at full rated speed

   On a 7.2 kW car, you should see roughly 7 kW going in on a 240V/40A circuit. If your wallbox is older or your circuit is undersized, you may be charging at 16A (about 3.8 kW) without realizing it — meaning a 'full overnight charge' isn't actually full. Most apps will tell you the live kW. If it's wrong, fix the circuit or the wallbox before you blame the car.

4. Find the service history

   Ask the seller for the maintenance booklet or pull a CARFAX. The big things to look for: aux battery replacements (should be every 4–6 years), brake fluid flush (DOT 4, every 2 years even on an EV), and any high-voltage system service. If service was done at a Mercedes dealer, the records will be on Mercedes's online system — a Mercedes service writer can pull it up by VIN.

5. Register for recall alerts

   Plug your VIN into [nhtsa.gov/recalls](https://www.nhtsa.gov/recalls) and into Mercedes-Benz USA's recall lookup. The 453 has had recalls for fuel pumps (gas only, doesn't apply to you), airbag inflators, and a couple of body items that do apply to the EQ. Recall repairs are free at any Smart-authorized Mercedes dealer regardless of how many owners back the campaign was issued.

6. Find an HV-certified shop before you need one

   Smart left North America in 2019. Not every Mercedes dealer wants to work on Smarts anymore, and high-voltage system work specifically requires HV-certified technicians. Most independent shops won't touch it. Some shops on the [Mechanic Directory](/mechanic-directory/) are Smart-experienced but may or may not be HV-trained — verify before booking. For low-voltage work (12V system, brakes, suspension, body, climate control) any Smart-experienced shop is fine. For anything touching the orange cables, ask the question first.

7. Read your specific Owner's Manual and the EV charging supplement

   The 453 EQ Owner's Manual covers the same chassis as the gas 453 plus EV-specific charging notes in a supplement. The supplement is what tells you the right cable types, the charging-port lockout sequence, and what the various dashboard symbols around the battery icon actually mean. Worth the hour. PDF link is in Downloads & Resources above.

8. Take a baseline scan

   A cheap iCarsoft V4.0 or a Foxwell NT530 reads Smart-specific modules — including the high-voltage / battery management modules on the EQ — the way a generic OBD2 reader can't. Pull all module faults once, save the report, and you have a starting point to compare against later. Generic OBD code lookups will mislead you on this car. Smart-specific tools are worth the $200, especially on the EV.

Watch this stuff before you wrench

A handful of videos that'll save you an afternoon — @SmartCarVideos first, then the deep enthusiast channels.

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  Smart ForTwo in-depth review

  Carbuyer

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  Should You Buy a Smart Car? (Test Drive & Review)

  High Peak Autos

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  453 owner walkthrough

  Owner review

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  New vs Old — Comparison of Smart Car 451 vs 453

  RVHaulers with Gregg

Browse the full Video Library →

Common problems & what to watch

The things that actually fail on this chassis. Cards link to deep guides with cheap-first checks and parts pricing.

Browse all fault codes →

Buying one? Look at these first.

Known weak points

• Battery degradation with no thermal management. The 453 EQ pack has no liquid cooling and no battery heater — it's passively cooled. Heat over years of summer parking damages the cells; cold simply removes range on the day. A 7-year-old Phoenix-area car may show 35–40 mi indicated where a Pacific-Northwest car of the same age shows 50+. There is no way to refurbish this short of cell-level work, and the aftermarket battery supply chain for the EQ effectively does not exist. Verify range on a test drive at full charge in your real climate, not on the 58-mi window sticker.
• 12V auxiliary battery aging. Yes, the EV has one too. The 12V AGM aux battery powers the SAM, central locking, and the contactor that engages the high-voltage pack. When it dies (typically 4–6 years), the HV system simply won't engage and the car won't 'start' even with the main battery full. Confusing as hell to diagnose if you don't know the car has a 12V battery at all. Symptoms: intermittent no-start, weird module errors on cold mornings, dash warnings that clear on a jump. Replace at 4–6 years preventively, not reactively.
• No DC fast charging — at all. Mid-cycle charging spec, never updated. There is no DCFC port on this car and no software unlock that adds one. Maximum onboard charging is 7.2 kW Level 2 (some markets only 4.6 kW). Road-tripping is essentially impossible because every charging stop is 3+ hours, and most public Level 2 stations charge by the hour. Plan around it or don't buy.
• Battery replacement is effectively impossible. Mercedes does not service the EQ pack anymore. There is no factory or dealer replacement program. A handful of independent EV shops can do cell-level repair if individual cells fail, but it is not common, parts are scarce, and pricing is unpredictable. If the pack fails outright, the car is functionally scrap. Price the car accordingly when buying — a cheap EQ with a degraded pack is not a bargain, it's a fixed-life asset.
• HV system shop work needs HV-certified techs. Anything touching the orange cables — pack, motor, charger, contactors — requires HV-certified technicians and the right insulated tools. Most independent shops won't take the work, and some Smart-experienced shops on the Mechanic Directory are not HV-trained. Verify before booking. For low-voltage work (12V, brakes, suspension, body, climate) any Smart-experienced shop is fine.
• EQ software quirks. The Electric Drive software has been quirky since launch. Known glitches include charging-plug detection failures (car thinks the cable is still attached when it isn't), erratic range estimation after a deep discharge, and pre-conditioning that won't engage in cold weather. Most have TSB-level fixes available at a Mercedes dealer if they'll still work on the car. None are catastrophic; all are annoying.
• Convertible roof microswitches (Cabrio only). Identical to the gas 453 Cabrio. If the soft-top stops mid-cycle or refuses to operate, suspect the position microswitches or the roof control module before assuming a hydraulic failure. Cosmic Cabrios in the UK is the global authority on these and ships internationally.
• Passenger occupant sensor (OCS) cluster faults. B00A068 / B00A07B / B00A096 surface together when the passenger-seat weight pad fails — same fault as gas 453, same SRS. The airbag light stays on and the passenger airbag goes inactive. Replacement is a Smart-experienced shop job since the part is matched to the SRS module.

Pre-purchase test drive checklist

1. Charge to 100% before the test drive. Note the indicated range. Drive a representative loop. Note the indicated range when you finish, and how many miles you actually drove. The math tells you the real pack health — not the original sticker.
2. Ask where the car has lived its life. Hot-climate cars (Phoenix, Vegas, Texas) will have meaningfully more pack degradation than mild-climate cars. This is not negotiable, it is physics on a passively-cooled pack.
3. Cycle the car from off → READY at least three times. If the dash is slow to wake or the contactor doesn't click in, the 12V aux battery is on its way out and that's a near-term cost.
4. Plug into your own home charger if possible. Verify the car charges at its rated speed (~7 kW on a 7.2 kW car, ~4.5 kW on a 4.6 kW car). Lower-than-rated charge speed can mean a charger module fault.
5. On a Cabrio: cycle the roof open and closed at least twice. Same mechanism as gas 453 — same wear points.
6. Check the auxiliary 12V battery date code (under the passenger floor on Fortwo). If it's 5+ years old, factor in a replacement immediately.
7. Plug in an iCarsoft V4.0 or Foxwell NT530 and pull all modules — including the high-voltage / battery management module. Stored history codes tell you what the seller cleared.
8. Cycle through every electrical accessory: windows, mirrors, climate (heating an EV pulls hard on the pack — pay attention to range drop), all four corner positions of the seats, both heated seats if equipped, the touchscreen.
9. Listen for the HVAC compressor on full A/C and full heat. The electric A/C compressor is one of the EQ's bigger wear items and replacement is not cheap.
10. Verify the maintenance booklet or pull a CARFAX. For an EV the records are shorter than a gas car, but you want to see brake fluid flushes, aux battery replacements, and any HV-system service.

Full PPI walkthrough →

Where to buy parts

Region-by-region. OEM via Mercedes is always available; the alternates below are owner-vetted.