Smart #3 HX31 — Problems & Common Faults
Weaknesses, engine ratings and buying advice
The smart #3 (HX31, from 2023) is the coupé-styled sister model of the #1: a low, 4.40 m long electric SUV with a sloping roofline, also on Geely's SEA platform and with Mercedes design. It shares its technology and 66 kWh battery with the #1 but is longer, lower and more sporting in character, with slightly more range thanks to better aerodynamics (up to around 455 km WLTP). At the top sits the Brabus dual-motor version with 315 kW system output and all-wheel drive, which accelerates the compact car to 100 km/h in under four seconds – performance that fully tests the body and road-holding. As with the #1, the main criticisms are software-related: instability and freezing of the infotainment, occasional restarts of the central system, oversensitive and intrusive assistance warning tones, and an often unreliable traffic-sign recognition that reports wrong speed limits – here consistent application of the OTA updates Geely delivers regularly helps. Mechanically and on the drivetrain there have been few issues so far, and build quality is decent. Long-term and reliability data is still limited. A practical point to consider: the coupé roofline costs rear headroom and some boot volume compared with the #1 – anyone who regularly carries rear passengers or a lot of luggage should check this on the test drive. As with the #1, it is advisable to cross-check the recall history via the VIN, since software and assistance have been reworked. Market status 2026: available as a young used car, the #3 appeals to buyers who prefer the more dynamic design over the more practical #1 and can live with the small practicality drawback. The base rear-wheel-drive version is the most sensible choice for most, while the Brabus remains a fun and prestige proposition with higher consumption. When buying, check software level, update history and battery condition (SoH), and deliberately test the assistance systems on a test drive.
Engine Overview
The Smart #3 HX31 is available with 2 engine variants — from 272 to 428 hp.
The dual-motor Brabus variant of the SEA platform combines front- and rear-axle motors into all-wheel drive and delivers substantially more system power with brutal acceleration, making the compact car surprisingly sporty. This performance comes at a price: tyre wear is high under brisk driving and real-world range drops noticeably compared with the single-motor version, especially in cold weather. When buying, check for even tread depth, current software level and battery state of health. The drive is mechanically low-maintenance; the critical areas are more the charging electronics, 12-volt battery and software topics.
- !! Underfilled front gearbox oil on early Brabus models
On early Brabus dual-motor AWD cars, the switchable front reduction gearbox was in some cases underfilled with oil at the factory (about 0.7 liters instead of the specified amount), damaging the front clutch gears. The same motor is shared with the Zeekr X.
Symptoms: Unusual noise or noticeable power loss from the front motor, especially under hard acceleration in AWD mode; front drive failure in extreme cases. - !! Rear motor bearing hum (Brabus too)
The rear motor bearing hum known from single-motor cars, per workshop reports, explicitly also affects dual-motor Brabus cars, since both variants share the same rear drive unit.
Symptoms: Continuous humming to rumbling noise from the rear starting around 80 km/h, growing louder with speed. - ! Vibration in steering wheel and cabin from 90 km/h on early cars
On early dual-motor Brabus models, vibration in the steering wheel and cabin appeared from around 90 km/h and persisted even after professional wheel balancing. Drivetrain components and rotating mass were suspected causes; newer cars are no longer reported to show this.
Symptoms: Noticeable vibration in the steering wheel and body from about 90 km/h, persists after tyre replacement and professional balancing.
+ 1 more engine weaknesses + vehicle weaknesses
The single motor on the Geely SEA platform sits at the rear axle and delivers the strong, linear acceleration typical of modern EV drives together with good everyday efficiency. The 66-kWh battery enables solid range, and thermal management keeps power electronics and cells within a favourable temperature window. When buying, check for current software levels, since the early generation was noticeably improved via updates, and inspect the charging curve and battery state of health. The drive itself is low-maintenance; the usual EV topics concern the 12-volt battery, charging electronics and software fault messages.
- !! Complete power failure from faulty 12V recharging
A software bug in the DC/DC converter on early software versions (before OS 1.3.0) prevented the 12V battery from being properly recharged from the HV battery. The car then becomes completely unresponsive and doors won't open.
Symptoms: Car stops responding after standing for a while, doors lock and won't open, app shows 'offline' despite sufficient main battery charge. - !! Rear motor bearing hum
From around 80 km/h onward, a number of early cars develop a deep, humming bearing noise from the rear motor that grows louder with speed. Workshops have confirmed defective motor bearings, and the fix requires removing the drive unit.
Symptoms: Continuous humming to rumbling noise from the rear starting around 80 km/h, growing louder with speed, resembling a distant diesel engine. - !! DC fast-charging power permanently far below spec
On individual cars, DC charging power permanently drops to around 25 kW even though the battery and charger allow far more. In several cases a faulty onboard charger was identified as the cause and replaced under warranty.
Symptoms: Car permanently charges at very low DC power (about 25 kW instead of the possible 130-150 kW), regardless of charger or battery preconditioning.
Vehicle Weaknesses
| Weakness | Cost | |
|---|---|---|
| Software Instability: Profile Saving and Spontaneous Logouts The vehicle software saves driver profiles (seat, steering wheel, mirrors) unreliably. Repeated spontaneous logouts from the user profile occur. The manufacturer describes many defects as 'series standard'. Symptoms: Seat position and settings are reset after a journey, unexpected logout from the user profile | Low | |
| Navigation System Fails Repeatedly Since April 2024, Smart #3 owners have reported navigation failures. Traffic sign recognition deteriorated after the July 2024 update. No permanent fix available so far. Symptoms: Navigation cannot calculate a route, stays offline, shows outdated charging station data | Low | |
| Traffic Sign Recognition Unreliable The traffic sign recognition incorrectly displays low speed limits on motorways. Partially worsened after the July 2024 software update. Persistent warning beeps until manually deactivated. Symptoms: Wrong speed limits shown on display, recurring warning signals at permitted speed | Low | |
| Door locks unreliable in cold weather In low outside temperatures, not all doors reliably open or lock via the electric door release. Several users report recurring failures of individual doors in winter. Symptoms: Individual doors cannot be opened or locked via remote, app or button in freezing conditions, sometimes requiring a mechanical emergency release. | Low | |
| Premature power limiting already from 60-70 percent charge Several users report that full system power is not available across the entire charge range but is noticeably throttled already around 60 to 70 percent state of charge - clearly earlier than in comparable EVs. Symptoms: Noticeable power loss when accelerating even though the battery still shows 60-70 percent charge; full power only available in the upper charge range. | Low | |
| 360-degree camera throws an error message in bends The 360-degree camera displays an error message every time the car goes through a bend, claiming it is not receiving speed data, even though the system otherwise works normally. Reproducible in cornering. Symptoms: Warning such as 'camera unavailable' appears while cornering, camera view briefly disappears, no permanent failure. | Low |
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Known Problems and Issues +
A total of 18 weaknesses have been documented for the Smart #3 HX31 (2024–2026) — 7 engine-related and 11 vehicle-related. Typical issues affect Electronics, Other, Body, Interior. Considered reliable: SEA-315 (Elektromotor Dual).
#3 (SEA-200, 2024–2026) — Be Careful: Complete power failure from faulty 12V recharging, Rear motor bearing hum, DC fast-charging power permanently far below spec. Power: 272 PS.
What to watch out for with the Smart #3? See the detailed listing of all engine and vehicle weaknesses in the sections above.
Frequently Asked Questions
What problems and weaknesses does the Smart #3 HX31 have? +
What should I look for when buying a used Smart #3 HX31? +
Which engine is recommended? +
Which Smart #3 HX31 engine is the most reliable? +
Which Smart #3 HX31 engine is the most fun? +
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Last updated: February 2026 · All information without guarantee