A significant High Court trial, (the Pan-NOx PDD Trial), begins today (October 13th, 2025) it’s a big step forward in the collective action against several vehicle manufacturers.
The goal of this 10-week hearing is simple: to answer the question ‘did manufacturers cheat the emissions test?’
The core allegation is that the vehicle manufacturers(Mercedes-Benz, Ford, Nissan, Renault, and Peugeot/Citroen) used "Prohibited Defeat Devices" (PDDs) in their diesel vehicles.
In simple terms, this info will be put forward:
- The Lab Test: When the manufacturers put their cars through the official, required laboratory emissions tests (the New European Driving Cycle), thevehicles successfully kept their harmful NOx (nitrogen oxides) emissions low.
- The Real World: The moment the cars left the lab and were driven on the road in normal conditions, the hidden software (the "defeat device") allegedly switched off or reduced the effectiveness of the emissions control systems.
- The Result: The cars then released significantly higher levels of NOx into the air than they were legally allowed to, and much higher than consumers were led to believe. The vehicle manufacturers are alleged to have done his to improve fuel economy and performance.
The trial will focus on a selection of 20 Core SampleVehicles (CSVs) to determine whether these vehicles definitely contained thesedevices and, if so, whether the devices were illegal under EU law.
Why This Trial is Important
If the Court finds that these manufacturers did use illegal defeat devices, it provides the legal foundation for every single claim in this group action.
If PDDs are found to exist, it means the manufacturers breached their obligations in two key ways:
- Breach of Contract (Mis-Sold Vehicles): The vehicle bought or leased was not of "satisfactory quality" and was not "as described." Claimants paid for a legally compliant vehicle but received one that contained an illegal device and emitted higher levels of pollution.
- Breach of Statutory Duty: The manufacturers directly violated the emissions law, and under relevant case law, consumers have a right to compensation for vehicles containing defeat devices.
A successful outcome in the PDD Trial would make the manufacturers legally liable and clear the path to determining the final amount of damages (compensation) owed to claimants.
Matthew Raines of Johnson Law Group who act for tens of thousands of claimants said: ‘After years of work, Monday 13th October marks the day of the start of the main liability trial in the Diesel Emissions Scandal, known as Dieselgate. At the end of the trial, if the allegations that car manufacturers cheated emissions tests by installing prohibited defeat device technology in the cars is proven, it will not only represent one of the biggest corporate wrongdoings in history, but pave the way for hundreds of thousands of claimants to receive compensation.’
We will continue to keep you updated as the trial progresses.
.jpg)