If you drive a diesel, you almost certainly have a diesel particulate filter (DPF) in the exhaust. It traps soot to cut harmful emissions, and every so often it needs to burn that soot off, called regeneration.
Euro 5 rules (2009) made DPFs standard on modern diesel cars, so every new diesel has at least one.
Signs of a DPF problem
- An orange DPF warning light on the dashboard (a box with dots inside). Don’t ignore it.
- Less power and slow acceleration
- Worse fuel economy
- Trouble starting, if the filter is badly blocked
- Unusual smells from the exhaust
- Left too long, damage to other parts such as the turbo
What causes a blockage
- Lots of short journeys, so the filter never gets hot enough to clean itself
- Missed or poor servicing. A well-looked-after DPF should last at least 100,000 miles
- The wrong engine oil. Some additives can block the filter
The law
Removing a DPF is illegal for road use. You can be fined up to £1,000 for a car and £2,500 for a van, and it can invalidate your insurance.
If your DPF light is on, get it checked early. We diagnose the cause first, then clean, regenerate or repair.
