Everything you ever needed to know about DPF Cleaning

Diesel vehicles are fitted with a diesel particulate filter (DPF), also known as a soot trap. They were designed to reduce emissions from diesel cars following the Euro 5 exhaust emissions legislation introduced in 2009, and have contributed largely to the reduction of CO2 emissions in the UK.

DPFs trap exhaust gases within a filter, turning them into soot. Their one drawback is their finite nature – soot collects within the trap and has to be cleaned by burning off or emptying. This regenerates (cleans) the DPF.

The regeneration process protects the DPF from soot buildup, which happens when the car doesn’t get up to temperature. This occurs most commonly in cities, where vehicles are used frequently but for short distances only.

DPF regeneration falls into two separate categories, passive and active.

Passive regeneration takes place when the engine is running at higher revs. You can ensure your vehicle’s DPF filter passively regenerates by driving for 15 minutes or more at a consistent speed in excess of 40 mph every few hundred miles.

If this isn’t possible, your car’s onboard computer will begin employing preventative measures in order to ensure the DPF filter doesn’t clog.

When passive regeneration cannot occur, the car’s computer raises the temperature of the exhaust gases. This kickstarts the regeneration process, which typically lasts 10 to 15 minutes.

Most modern cars feature a stop-start engine system. During an active regeneration period, this will usually be switched off by the car computer. The DPF warning light usually comes on if the passive regeneration process is interrupted on a number of occasions. This tends to occur when a car is used for several short, consecutive urban journeys, which result in the car failing to get up to the temperature required for active DPF regeneration.

If the warning light does come on, your best option is to find a stretch of dual carriageway or motorway and drive at 40+ mph for fifteen minutes. This should give the filtration system a chance to regenerate completely.

Failure to facilitate DPF regeneration can result in increased fuel consumption, as well as poor engine performance.

If you continue to ignore the warning light (and don’t manage to encourage active DPF regeneration), the filtration system will become too clogged to clean itself. It’s at this point you’ll need to pay for a professional cleaning service.