As of July 2023, particle measurement (PN measurement) will also be carried out for diesel vehicles from pollutant class Euro 6/VI as part of the emissions testing (ET). This is designed to reliably identify vehicles that do not (or no longer) comply with the limit values. An initial evaluation of the TÜV association resulted in a rejection rate of 3.4 percent. One striking element is that these are mainly vehicles with high mileage. So the new measure clearly successfully identifies vehicles that do not comply with the limit values.
Vehicles that do not pass the emissions test must then be improved immediately. TÜV welcomes the effectiveness of the new process and even wants to go one step further: It is in favour of extending the process to vehicles of pollutant class Euro 5b and also to direct injection petrol vehicles from class 6. With the help of the new measuring technology, it is also possible to ensure that the filters also function properly in these vehicles. Vehicles with excessive pollutant emissions can also be identified. An initial evaluation of the new measurement method also shows that the failure rate of the vehicles increases with increasing mileage. For example, the failure rate with a mileage of up to 50,000 kilometres is just 2.8 percent, with a mileage of over 160,000 kilometres, the figure increases to 4.7 percent. This initial evaluation covers a total of 950,809 vehicles.
New vehicles can also fail the particle measurement test
This is not something any car buyer expects, but new diesel vehicles can also fail the first emissions test/ particle measurement. These vehicles are usually only three years old in the first emissions test. This is the fault of the particulate filter. Unfortunately, it is not a cheap undertaking for the vehicle owner, as the repair with replacement of the filter can cost up to 3,000 euros. And unfortunately, this doesn't even constitute a warranty claim. The reason for this is the fact that different measurement methods, including limit values, are used for the type approval of vehicles or for particle measurement as part of the emissions test:
The difference between measuring methods:
For the type approval of vehicles, a certain limit value for the total number of particles per kilometre must be adhered to. However, this method is too complex in terms of costs and effort. Therefore, a different method is used for the emissions test. The number of particles per exhaust volume is measured here. However, the above procedure is legally binding for vehicle manufacturers. It is therefore also difficult for the vehicle owner to make claims here. Added to this is the fact that this usually only occurs after three years and the normal liability for material defects is two years from the date of purchase. However, some manufacturers are now reacting with a goodwill gesture. It is advisable to submit an application for goodwill through a contracted workshop.
In short:
The new measurement method appears to have proven itself and can reliably detect defective particulate filters. With the previous exhaust gas opacity measurement, it was not possible to detect the small particles emitted by modern engines. This is now possible. However, it can cause some trouble for the vehicle owner. Not only does the vehicle have to go to the workshop, it can also result in high costs. For the vehicle owner, there's also no guarantee that they won't have to cover the costs. So there is certainly room for improvement here. Perhaps harmonizing measurement methods would also be a good idea.