The ECJ classifies the thermal windows as illegal

The Advocate General at the European Court of Justice (ECJ) classifies the thermal windows as illegal in the diesel proceedings against Volkswagen and Porsche. The exhaust systems used by car manufacturers, in which exhaust gas cleaning is stopped outside a specified temperature range and above a certain altitude, violate European laws, explained the Advocate General in his closing argument. Such a device cannot be justified with the protection of the engine from damage or accident and the safe operation of the vehicle if it primarily serves to protect attachments. The judges at the ECJ often follow the line of argument of the Advocate General, but are not bound by it. Advocate General Athanasios Rantos pointed out that the thermal window was not representative of actual driving conditions. The control takes effect when the outside temperature is below 15 and above 33 degrees as well as when driving in mountains over 1000 meters altitude and throttles or stops the exhaust gas cleaning. Rantos pointed out that the average temperatures from 2017 to 2019 in Austria, Germany and other European countries were well below 15 degrees. Due to the topography of Austria and Germany, the cars often drive at altitudes of more than 1000 meters. The software in question therefore reduces the effectiveness of the emissions control system under normal conditions of use and normal vehicle operation and represents a "shutdown device". The Advocate General explained that exceptions to the prohibition of defeat devices are permitted if they protect the engine and ensure the safe operation of the vehicle. A shutdown device that primarily serves to protect parts such as the exhaust gas recirculation valve, the EGR cooler or the diesel particulate filter is not included. In December, five years after the diesel scandal at Volkswagen, the judges pronounced a groundbreaking verdict on the use of emissions software in diesel cars. They decided that the general ban on software for exhaust gas manipulation would be undermined if it were possible to protect the engine from soiling and wear through exemption regulations. The manufacturers exploited loopholes in EU law by reducing or completely switching off the exhaust gas cleaning of diesel engines at cool temperatures. Almost all car manufacturers use thermal windows and argue for it with the engine protection.