Diesel Particulate Filter (DPF) Inspection

Within a few years, once the revised Directive of the European Parliament and of the Council enters into force, measuring the particulate matter emissions of vehicles will become a mandatory procedure during vehicle inspections, so, rather than waiting until the last minute, we recommend checking whether your car’s particulate filter is in good working order and won’t cause major inconveniences in the future.

The diesel engine smoke test conducted during the technical inspection on this day measures only the light transmittance of the exhaust gas (m⁻¹). The resulting PN (Particle Number) measurement indicates the number of particulate matter particles per cubic centimeter of exhaust gas. According to practices in other countries, the permissible limit for vehicles ( Euro 5b emission class and newer) with a properly functioning DPF is 250,000–1,000,000 particles/cm³. Results exceeding this limit indicate malfunctions in the engine and/or the exhaust system.

Particulate matter testing during vehicle inspections for diesel engines is required in the following EU countries:

• In Germany, effective January 1, 2023
• In the Netherlands, effective July 1, 2022
• In Belgium, effective July 1, 2022
• In Switzerland, effective January 1, 2023
• In Latvia, effective January 1, 2025

According to European Commission Recommendation (EU) 2023/688 of March 20, 2023, on the measurement of particulate matter during periodic mandatory technical inspections of vehicles with compression-ignition engines, for vehicles of the Euro 5b and higher emission classes, the particulate matter concentration in the exhaust system should not exceed 1,000,000 (^1/cm³).

The results of particulate matter concentration measurements make it possible to evaluate the exhaust gas aftertreatment equipment (particulate filter) in a vehicle's exhaust system—specifically, how effectively it captures particulate matter emitted from the internal combustion engine into the environment.

You can read more about exhaust gas neutralization equipment installed in cars on the website of the Lithuanian Association of Technical Inspection Companies “Transeksta”: https://www.vta.lt/priezastys-ir-pasekmes-vairuojant-automobili-be-katalizatoriu-ir-filtru/