Smart Common Problems & Known Faults

How reliable are Smart cars?

Our database covers 6 Smart models and 30 documented faults across the range. Of these, 12 are classified as dangerous and a further 14 as major. Dangerous faults are those that can compromise vehicle safety or lead to complete mechanical failure if left unaddressed.

According to DVSA MOT test data, Smart models fail at an average rate of 25.0%, which is above the 22.7% average across all manufacturers in our database. Reliability varies considerably between models. The Roadster 80 Auto(rhd) is the strongest performer at just 24.8%, while the Roadster Coupe 80 Auto(rhd) has the highest failure rate at 25.1%.

If you are considering a used Smart, researching the specific model and generation you are looking at makes a real difference. The most common failure areas across the range are brakes and suspension, though each model has its own particular weak points. This page gives you a complete breakdown by severity, the models affected, and what repairs typically cost at UK garages.

Smart reliability summary

Where Smart problems occur

Understanding which systems are most prone to failure helps you focus during a test drive or pre-purchase inspection. Here is how Smart's 30 known issues break down by area.

Brakes problems dominate, accounting for 12 of the 30 faults we track (40%). Issues in this area include Flexible brake hose deterioration (W450) and Brake pipe corrosion (W450). The most affected models are the City Passion 61 (2), the Fortwo Passion 71 (2), the Fortwo Passion MHD (2).

Suspension is the next most common area, with 11 documented faults (37%). Common faults here include Suspension component excessive wear (W450) and Front coil spring fracture. The most affected models are the Roadster Coupe 80 Auto(rhd) (3), the Fortwo Passion MHD (2), the Fortwo Pulse MHD (2).

We also track 3 ancillaries faults across the range (10%). Problems to watch for include Engine mounting deterioration (W450) and Engine mount failure causing excessive movement. The most affected models are the City Passion 61 (1), the Fortwo Passion MHD (1), the Roadster 80 Auto(rhd) (1).

Engine rounds out the top problem areas with 1 known issues (3%). Notable issues include Lambda sensor failure (W450). The most affected models are the City Passion 61 (1).

Known Smart faults by severity

Every fault in our database is rated by severity based on its potential safety impact and typical repair cost. Below is a sample of issues at each level, with links to the affected model pages where you can read the full details.

Top issues across the Smart range

The most common and severe problems found across all Smart models, ranked by severity and how many models are affected.

Problems by Smart model

We track faults across 6 Smart models. Each model page includes every known issue, generation-specific details, UK repair costs, and MOT failure data. Select a model below to see its full breakdown.

What to check before buying a used Smart

Every used Smart deserves a thorough inspection, but knowing the common weak points for your target model gives you a serious advantage. Since brakes faults are the most common across the range, pay particular attention to this area during any viewing or test drive.

The 12 dangerous-rated faults deserve special attention. These include Flexible brake hose deterioration (W450), Brake pipe corrosion (W450), Brake pipe corrosion and damage. Any of these can compromise safety or result in repair bills running well into the thousands.

A complete dealer service history is one of the strongest indicators of how well a Smart has been looked after. Many of the faults on this page are preventable or can be caught early through regular servicing. If the seller cannot produce service records, treat that as a significant red flag.

Check the MOT history carefully too. With a 25.0% average failure rate across the Smart range, some advisories and minor failures are normal over the life of any car. What matters is the pattern: recurring failures in the same area suggest an underlying problem, while a history of clean passes is encouraging.

Smart repair costs: what to expect

Across all documented faults, the average Smart repair costs between £198 and £377 at an independent garage. At the top end, the most expensive single repair can reach £1,200 or more. Main dealer rates are typically 30% to 50% higher across the board.

The single most expensive Smart repair in our database is Suspension component damage (C452), which can cost £1,200–£2,500 at a main dealer.

These figures are based on reported UK repair costs and serve as a guide. Actual prices will vary depending on your location, the garage, and the parts required. Getting quotes from two or three specialists before committing to any major work is always worthwhile.