That's the warning from reconditioning parts specialist DPF Clean Team, which says it could be triggered several vehicle issues, including: faulty temperature or pressure sensors; failed EGR (exhaust gas recirculation) valve; problems with exhaust and injection systems; and faulty glow plugs – even using the wrong type of oil.
The company has recently taken on a specialist repairer to fix broken ceramic filters on DPFs – a problem it says is caused by mechanical failure, or by a driver knocking the unit on a difficult journey.
"We receive many calls a day from people whose DPF warning light has come on and many automatically think that it's because of a blocked filter," comments DPF Clean Team managing director Cameron Bryce.
"We do our best to solve most DPF issues and welcome all enquiries, but there are many faults that we will refer to a garage to rectify, and many that can be solved by the vehicle owner themselves."