In addition to manipulations at VW, the exhaust gas scandal also involved so-called “thermal windows”, which were also used by other manufacturers such as Mercedes. The ECJ has now decided that these systems are only permitted within very narrow limits.

A thermal window that reduces exhaust gas cleaning in diesel vehicles at normal temperatures is not permitted. The European Court of Justice (ECJ) said on Thursday in Luxembourg that an exception could apply if it can be proven to protect the engine from serious risks that pose a danger when driving. Even then, such a defeat device would not be permitted if it mostly had to run under normal conditions. (Az. C-128/20 and others)

For exhaust gas cleaning in diesel, some of the exhaust gases are fed back into the engine and burned again. With the thermal window, this is reduced or stopped when the outside temperatures are particularly warm and, above all, cooler, which is why the vehicles then emit more nitrogen oxides. The cases at the ECJ concerned lawsuits from Austria against Volkswagen and two car dealers. The car buyers demanded the purchase price back.

The Austrian courts dealing with the cases asked the ECJ whether the thermal window was permissible. However, its assessment is also binding for other national courts, which is why it can affect cases throughout the EU. The Austrian courts must now examine whether the thermal window was necessary to protect the engine in the specific cases and whether there was no other solution.

The emissions scandal is the biggest scandal in German automotive history. It cost Volkswagen and other companies billions and revealed dramatic undesirable developments, especially in the VW group. But the scandal is also being used politically to push through goals such as driving bans. How did the diesel drama come about? What is actually behind the “German Environmental Aid”? And why are there only diesel driving bans in Germany, some of which are less than four years old, based on the fact that measured values ​​are exceeded locally? FOCUS Online has been looking behind the scenes since 2015.

They assumed that the low-emission mode was only guaranteed when the outside temperature was between 15 and 33 degrees Celsius and at an altitude of less than 1000 meters. Volkswagen asserted before the ECJ that it was about the charge air temperature in the engine, which was higher on average. However, the ECJ has now declared that the referring national court alone is responsible for assessing the facts of the case.

If compliance with the emission limit values ​​was only guaranteed at an outside temperature between 15 and 33 degrees and below 1000 meters in altitude, it would be a defeat device. He also pointed out that lower temperatures are normal in the EU and the exhaust gas limits must be observed even then.

Even if a defeat device serves to protect against sudden dangers but has to function for most of the year under normal operating conditions, this is not permissible. Otherwise the exception could be applied more frequently than the ban, the ECJ explained. He did not rule out reimbursement of the purchase price – but the national courts have to decide on this in individual cases.

After the decision, the car manufacturer Volkswagen stated that it saw its legal opinion confirmed: “According to the criteria set out by the ECJ in its judgment, the thermal windows used in vehicles of the VW Group remain permissible.” They protect against immediate risks for the driver Engine in the form of damage or accident.

A VW spokesman told FOCUS Online: “The exhaust gas recirculation of the EA189 vehicles affected by the procedure is up to an outside temperature of 10 °C and is therefore 100% active for most of the year. The effects of the judgment on Volkswagen are therefore minor. National authorities and courts still have to decide on a case-by-case basis whether a specific thermal window is permissible. Civil lawsuits based on an alleged claim for damages based on the presence of a thermal window will continue to be unsuccessful.”  VW points out that the 15 degrees in the ECJ decision refers to the intake temperature measured in the engine, which is 5 degrees warmer than that outside temperature.

The chairman of the Austrian consumer protection association, Peter Kolba, said: “This puts an end to the arguments of diesel manufacturers and German authorities that these thermal windows serve to protect the engine and are therefore legal.” Other legal experts are now seeing a new one Wave of lawsuits rolling towards VW and other manufacturers. “Today’s verdict has once again caught up with VW in the emissions scandal. Several million vehicle owners could now take action against the Wolfsburg group. The processing of the scandal will certainly drag on for several more years,” commented the lawyer Claus Goldenstein. He is the owner of a law firm that represents more than 42,500 clients in connection with the emissions scandal.

The German Federal Motor Transport Authority had approved software updates with thermal windows. The updates were installed by Volkswagen, among other things, to fix the illegal manipulations in the diesel scandal. In fact, most car manufacturers use thermal windows. The Federal Court of Justice in Germany has so far rejected claims for damages by vehicle buyers solely because of the thermal window.