So-called “temperature window” software used by Volkswagen to control emissions in various diesel engines is illegal, according to a key adviser to the Court of Justice of the European Union (CJEU).
The finding, part of deliberations in a case brought against the German automaker by an Austrian consumer group, is the latest in a long line of legal setbacks experienced by Volkswagen since evidence emerged in 2015 that it had developed measures to cheat diesel emissions tests in North America.
At the center of the finding delivered by the CJEU advocate general, Athanasios Rantos, is a software package that uses various parameters, including temperature readings, to alter emissions.
Rantos says the software, which operates within a temperature window, is illegal even if, as claimed by Volkswagen, it prevents premature aging and clogging of diesel engines.
The software is used to control a valve that recirculates exhaust gases emitted by the engine, albeit within a narrow temperature range between 15-30° C (59-91.4° F).
In temperatures outside the temperature window, the exhaust gas is emitted without the recirculating process, leading to higher levels of nitrogen oxide (NOx) emissions.
In his finding, Rantos says the temperature-dependent control of exhaust emissions is not representative of real world driving conditions in Austria and neighboring European countries, including Germany, where the temperature is often lower than 15° C.
A further parameter within the software also shuts down the circulating process at an altitude of 1,000 m (3,280 ft.). Rantos points out vehicles are often driven above this altitude.
The actions of the CJEU are not bound by the opinion of the office of the advocate general, but it traditionally follows its rulings.
Along with possible repercussions for the Volkswagen Group, the finding by Rantos could also affect legal cases brought against other European automakers, including Mercedes-Benz parent company Daimler.
In January, the German Federal Court of Justice ruled the temperature-dependent control of the exhaust gas recirculation systems used in the Mercedes-Benz C220 CDI does not create an entitlement to recover damages on the basis of unconscionability.
The German court also determined the temperature window software used by Mercedes-Benz is not comparable to the software used by the Volkswagen Group, because the functionality of the former “does not distinguish whether a vehicle is on a test stand or in real world driving conditions, and in principle operates under the conditions that are decisive for the test cycle in the same way on the road as on the test stand.”