The Fiat Chrysler Group, Ford and Volkswagen led a 4.6% decline in European car registrations in January, industry data showed.
Car sales were dampened by an economic slowdown in euro zone economies and consumer jitters over Brexit and trade.
Registrations dropped to 1.20 million cars in the European Union (EU) and European Free Trade Association (EFTA) countries from 1.25 million a year earlier, the Brussels-based Association of European Carmakers (ACEA) said today.
Fiat Chrysler sales fell by 14.9%, Ford by 6.6% and Volkswagen Group by 6.4%, according to the data.
Renault's alliance partner Nissan also recorded a 24.7% decline.
The drop came after the tougher new Worldwide Harmonised Light Vehicle Test Procedure (WLTP) became mandatory from the start of September, forcing some carmakers to halt deliveries of some models that had yet to be certified.
European car sales had surged in the month before the new procedure became effective and have declined every month since.