For drivers across Germany, the annual roadworthiness inspection, known as the Hauptuntersuchung, is a serious matter. Overseen by the country’s main technical inspection agency, TUV, this annual checkup sifts through millions of vehicles to see which ones are ready for the road and which ones need immediate work.
The fresh 2026 TUV-Report analyzed 9.5 million inspections performed between July 2024 and June 2025, and delivered some painful news: vehicle quality is falling. Overall, 21.5 percent of all cars – more than one in every five – failed their yearly inspection due to a “significant” or “dangerous” defect.
While reliability issues affect cars of all types and ages, the spotlight this year fell on EVs, specifically one brand. For the third year in a row, models from Tesla found themselves parked at the bottom of the league table, suffering the highest rates of mechanical failure. The Tesla Model 3, covering vehicles aged two to three years, showed a defect rate of 13.1 percent. That means one in every 7.6 of these electric cars did not pass the safety check on the first try.
The news was even worse for its sibling. The Model Y posted an alarming 17.3 percent defect rate in the same age group, earning the title of the worst-ranked vehicle TÜV has seen in this category over the past decade. Inspectors found the most common problems across the brand involved the axle assembly, suspension, brakes, and lighting.
The reliability struggle is not a universal problem for all EVs. The data clearly shows that electric cars can be extremely reliable. In the same critical two-to-three-year-old category, the electric Mini Cooper SE proved itself far more dependable with a low defect rate of just 3.5 percent. Further proving the point, the Fiat 500e topped the small car class among nearly-new vehicles, demonstrating that electric motoring does not need to lead to major maintenance issues.
With the overall proportion of cars facing minor defects also rising to 12.3 percent, the report confirms that owners across the board are seeing more mechanical trouble than in previous years.
For drivers holding onto their vehicles for a decade or more, the TUV introduced a new award this year for Long-Term Quality, recognizing brands whose vehicles aged 10 years and older maintain the lowest average defect rate for safety-related faults. Mercedes-Benz took the gold medal, showing an 18.5 percent defect rate for its oldest vehicles.
Audi followed close behind in second place with a 19.2 percent defect rate, while Toyota took the final podium spot with 22 percent. It is worth pointing out that the defect rate for Mercedes’ vehicles aged over a decade is roughly the same as the defect rate for a two-to-three-year-old Model Y.
Electric cars faced the most scrutiny at the bottom of the rankings, but the report also exposed reliability problems for several well-known gasoline and diesel models. Poor performers in older categories included the BMW 5-series and 6-series (in the four-to-five and eight-to-nine-year age groups), the Dacia Duster (in the six-to-seven and ten-to-eleven-year age groups), and the Renault Clio (among the oldest vehicles at 12 to 13 years old).
The 2026 TUV-Report is a clear warning to potential buyers and current owners alike: whether you drive a combustion vehicle or one of the newer EVs, the quality of the parts and the care you give your car are more important than ever.
