This issue can result in significant mechanical problems, increased repair costs, and, in some cases, may even require a full engine replacement. A faulty DPF system can also impact vehicle safety, fuel efficiency, and environmental performance. This may lower the car’s resale value and create unexpected financial strain for owners. If you have owned or leased one of the affected vehicles, you may be eligible for compensation — even if you’ve since sold the car or have not yet faced expensive repairs.
Whilst operating, diesel combustion engines generate pollutant emissions. The DPF system is a device designed to capture, convert, and remove these emissions through a combination of filtering, combustion, and chemical reactions.
Over time, the DPF system clogs with particulate matter and must be cleared to prevent blockages. To do this, the DPF system undergoes a process called regeneration, which burns off the build‑up of soot at high temperatures.
A diesel-powered engine can undergo two types of regeneration: Passive Regeneration and Active Regeneration.
Passive Regeneration occurs automatically when the exhaust system reaches a sufficiently high temperature, typically during prolonged high‑speed driving.
Active Regeneration occurs if the vehicle does not reach high enough temperatures during regular urban driving. Additional fuel is injected to raise the exhaust temperature and initiate the burn‑off process.
Under certain conditions, the DPF system in the affected vehicles does not successfully complete the regeneration process. As a result, the DPF becomes blocked with particulate matter, causing the vehicle to experience a range of problems.
These problems can include excessive smoke and foul‑smelling exhaust gas, frequent dashboard warnings advising that the DPF system is full, and significantly shortened service intervals.
There have also been incidents where the vehicle has entered “limp mode”, an emergency measure that limits acceleration to protect the engine from suffering significant damage.
