The highest federal court in Germany has determined that car manufacturers must provide compensation to owners of diesel cars equipped with illegal emission manipulation devices.
This decision comes after a lengthy class-action lawsuit filed against Audi, Mercedes-Benz, and Volkswagen by diesel car owners in Germany.
The federal court’s ruling overturns previous dismissals by state courts, which had referred the claims of diesel car owners to lower courts of appeal.
In its ruling, Germany’s federal court stated that the car manufacturers bear the burden of proving that their diesel emission manipulation devices are not illegal.
As a result of the ruling, owners can now claim between 5% and 15% of the purchase price of their diesel cars that are fitted with illegal emission manipulation devices. This judgment has direct implications for similar lawsuits against other car manufacturers in Germany.
Owners had argued that the value of their diesel cars had been negatively affected due to the use of illegal diesel emission manipulation devices.
The judge referred to several diesel emission manipulation devices, including the so-called “thermal window software programs” allegedly used by Audi, Volkswagen, and Mercedes-Benz.
“Thermal window software program” refers to a device that reduces or disables the nitrous oxide filtering effect of the selective catalytic reduction system within a specific temperature range in a diesel exhaust system.
When diesel cars are started under cold conditions, there is a risk of condensation buildup in their selective catalytic reduction filter systems.
The car manufacturers have argued that the use of thermal window software programs, which reduce or disable the filtering effect, helps prevent condensation and the risk of rust buildup, thereby protecting the engine.
However, this practice results in significantly higher nitrous oxide and particulate emissions than claimed by the manufacturers.
Volkswagen, when questioned about the ruling, stated that its diesel emission systems are not illegal and expects the court to continue rejecting any compensation claims.
Mercedes-Benz argued that European regulatory authorities considered thermal window software programs permissible until July 2022. Therefore, they believe the use of such programs cannot be seen as negligence.