Directive 98/69/EC of the European Parliament and of the Council of 13 October 1998 relating to measures to be taken against air pollution by emissions from motor vehicles ( 6 ) requires the introduction, from 2000, of on-board diagnostic (OBD) systems for petrol-driven cars and light commercial vehicles to monitor the functioning of the vehicle’s emission control system in service. Similarly, from 2003, OBD systems are required also for new diesel vehicles.