DPFs have been fitted for over a decade as part of the vehicle’s exhaust system to reduce harmful exhaust emission. They work by trapping “soot” particles created during the normal operation of a diesel engine and are meant to be self-cleaning.

However, Glasgow-based finance broker First Vehicle Leasing is warning that drivers of diesel vehicles used mainly for city driving and stop-start commuting are likely to face issues with the vehicle’s filter becoming clogged.

The firm says that if drivers see a warning light appear on their dashboard, they should take steps to ensure that they drive at higher speeds on a motorway or dual carriageway above 40mph for a period of time to “regenerate” the DPF. 

‘If you do not do this, you may need to have the filter replaced, and this cost is unlikely to be covered under the vehicle’s warranty,’ said Andy Watson, business development manager at First Vehicle Leasing.

With DPFs costing in the region of £1k to £3k, such bills could prove hefty for fleets.

Watson added: ‘If you plan to drive exclusively in cities, or know your main journeys will be stop-start at low speeds, you may wish to consider the option of leasing a petrol-engined vehicle, which can be just as economical as a diesel. Hybrid cars can offer even better fuel economy.’