A High Court judge has ruled that several major car makers’ vehicles did not contain devices that would have allowed them to cheat emissions tests.
More than a dozen manufacturers are being sued by approximately 1.6 million motorists over claims that many diesel vehicles made since 2009 contained “prohibited defeat devices” (PDDs).
The cases involved 20 “specimen vehicles” made by five manufacturers: Mercedes-Benz, Renault, Nissan, Ford, and Peugeot and Citroën.
880,000 motorists claimed they were misled about emissions testing.
The ten-week trial ended in March and, in a 369-page judgment handed down today, Lady Justice Cockerill said most of the strategies did not constitute PDD, except one used in Mercedes cars, which was scrapped in 2015, and another used in some Peugeot-Citroen vehicles.
The judgment said: “The Court rejected most of the major allegations made against the manufacturers whose vehicles were examined during the hearing.”
It added: “In the majority of cases, the Court found that the relevant tactics do not constitute a prohibited defeat device.”
Mercedes welcomed the verdict but said it disagreed with the court’s ruling that one of four of its sample vehicles was non-compliant before the software update.
The German carmaker said: “In our view, the emissions control software methodology is justified on both technical and legal grounds. We are actively considering all our available options, including a possible appeal.”
Peugeot-Citroen has not yet commented.
Those taking legal action either bought, leased or otherwise acquired a diesel vehicle manufactured by one of the companies, the majority of whom live in England and Wales.
The barrister for the motorists told the trial that devices installed in the cars allowed the vehicles to detect and change the amount of harmful emissions produced during testing so that they could come under emissions regulations.
However, the Court found that not every calibration or emissions-control strategy is a defeater device.
The judge found, “To find a defeat device, there must be an intent to operate the emissions control system differently when it knows it is being tested.”
“It was not enough for claimants to merely establish that the challenge strategies reduced the effectiveness of emissions-control systems outside relevant test conditions.”
Counsel for the claimants noted that Justice Cockerill said, “If an alternative approach to the meaning of ‘defeat device’ were adopted, a large number of devices would be installed, including devices in cars of every major manufacturer”.
James Oldnall, managing partner of Milberg, which represents some of the claimants, said: “We are pleased that the court has ruled that Mercedes installed illegal defeat devices in the same manner as Volkswagen in 2015.
“The fight on this matter is not over, but the first domino has fallen. We are on the right track and will continue to apply pressure to hold these carmakers accountable.”
A further trial has also been scheduled for October this year to determine the consequences of any actionable breaches and any issues relating to damages or other remedies.
The case examined only 20 sample vehicles made by Mercedes-Benz, Renault, Nissan, Ford and Peugeot and Citroën. The comprehensive case also includes models made by Opel and Vauxhall, Volkswagen and Porsche, Jaguar Land Rover, BMW, FCA and Suzuki, Volvo, Hyundai-Kia, Toyota and Mazda.
The Dieselgate scandal first came to light in September 2015, when the US Environmental Protection Agency accused Volkswagen of installing software on diesel cars to lower the cars’ nitrogen oxide emissions readings – known as “defeat devices”.
The software recognized when cars were undergoing official emissions tests and triggered systems designed to reduce the production of nitrogen dioxide, a gas that can cause respiratory problems.
But when the cars were used on the road, the system was turned off to improve performance. The net result was that cars in everyday use produced significantly more pollution than the official figures indicated.
VW later admitted that the defeat devices were used deliberately to circumvent emissions tests in the US, and were fitted to approximately 11 million cars worldwide.
It has paid out about £27.8 billion in fines and compensation worldwide over the scandal, mostly in the US. This also includes £193 million paid to 91,000 British motorists.
As part of the High Court case in London, barristers for the car owners cited a report by the Center for Research on Energy and Clean Air.
It found that excess nitrogen oxides – emissions produced by diesel engines – caused 124,000 premature deaths and 98,000 new cases of asthma in children in the UK and Europe between 2009 and 2024.
