EC Directive 1999/96/EC, which amended Directive 88/77/EC on heavy duty engine emissions, introduced the Euro 3, Euro 4, Euro 5 and Enhanced Environmentally friendly Vehicle (EEV) emission limits. Furthermore, 1999/96/EC also specified that, from 01/10/2005, all new types of vehicle would be required to demonstrate the durability of their emissions control systems and be fitted with an on-board diagnostic (OBD) system. The specific requirements and test procedures for emissions durability and OBD systems were not included in the Directive at its time of publication, but the European Commission were tasked with proposing suitable provisions.
With the publication of 2005/55/EC, which is a recast (i.e. a consolidation) of 88/77/EC and all of its amendments, the durability requirements and OBD threshold values are now specified. However, a further amending Directive was published on 29th November 2005 (Directive 2005/78/EC) to fully specify the technical requirements and test procedures for emissions durability and OBD systems.
The durability requirements will be implemented from 01/10/2005 for all new types of vehicle, and from 01/10/2006 for all new vehicles, and require demonstration of the emissions control system for the following periods:
Durability (Useful Life)
| N1 and M2 category vehicles (i.e. light goods vehicles and minibuses). | 100,000 km or 5 years |
| N2 and N3 category vehicles (i.e. heavy goods vehicles) with a gross vehicle weight not exceeding 16000 kg. M3 category vehicles of classes I, II and A (i.e. buses), and class B (i.e. coaches) with a gross vehicle weight not exceeding 7500 kg. |
200,000 km or 6 years |
| N3 category vehicles (i.e. heavy goods vehicles) with a gross vehicle weight exceeding 16000 kg. M3 category vehicles of class III and class B (i.e. coaches) with a gross vehicle weight exceeding 7500 kg. |
500,000 km or 7 years |
The requirements for the mandatory fitment of an OBD system are applicable to compression ignition engines from 01/10/2005 for all new types of vehicle, and from 01/10/2006 for all new vehicles. For gas fuelled engines, the requirements are applicable from 01/10/2008 for all new types of vehicle, and from 01/10/2009 for all new vehicles. The OBD system must be capable of signalling the presence of a fault to the driver, if the following threshold limits are exceeded:
OBD Threshold Limits
| Mass of oxides of nitrogen (NOx) | 7.0 g/kWh |
| Mass of particulates (PT) | 0.1 g/kWh |