Signs of a blocked DPF
- DPF warning light on the dashboard
- Noticeable loss of power or sluggish acceleration
- Increased fuel consumption
- Smoky or unusually smelling exhaust
- The engine going into "limp mode"
Diesel particulate filters are built to burn off trapped soot during longer, faster drives. Lots of short journeys and stop-start city driving don't give the filter enough heat to do this on its own, so soot builds up over time.
Cleaning and regeneration, not replacement
In most cases a blocked but otherwise sound DPF can be cleaned and force-regenerated on-site, restoring performance and clearing the warning light for a fraction of the cost of a new filter, which on many vehicles is one of the more expensive parts to replace.
Why it matters for your MOT
Excessive smoke, or a DPF that's been tampered with or removed, is an MOT failure point. Getting a blocked filter properly cleaned rather than stripped out keeps the car both road-legal and running properly.
Other services you might need
Frequently asked questions
What causes a DPF to block?
Diesel particulate filters are designed to burn off trapped soot during longer, higher-speed drives. Regular short journeys and stop-start city driving don't give the filter enough heat to do this, so soot builds up over time until it triggers a warning light or noticeably reduces performance.
Is DPF cleaning cheaper than replacement?
In most cases, yes, significantly. A blocked but otherwise sound DPF can usually be cleaned and regenerated for a fraction of the cost of a new filter, which on many vehicles is one of the more expensive single parts to replace.
Can a blocked DPF fail an MOT?
Yes. Excessive smoke or a DPF that's been tampered with or removed is an MOT failure point. Getting a blocked filter properly cleaned rather than removed keeps the car both compliant and running as it should.