With most vehicles the DPF warning light will illuminate to notify you that the unit is becoming blocked and requires regeneration. When conditions are met for regeneration, it will attempt to burn off the built up soot using either an active, or passive regeneration. If the regeneration is unable to occur or fails you may be treated to an additional warning light on your dash. This usually occurs when the DPF is blocked beyond the point at which a normal regeneration will clear it and indicates a garage visit is required.
Loss of power?
DPF Warning light on?
Your vehicle is in limp mode?
Frequent attempts at DPF regeneration?
DPF regeneration is failing?
Strong smell of diesel?
Vehicle is smoking excessively?
Oil level is increasing?
High fuel consumption?
From February 2014 the inspection of the exhaust system carried out during the MoT test will include a check for the presence of a DPF.
A missing DPF, where one was fitted when the vehicle was built, will result in an MoT failure. A vehicle might still pass the MoT visible smoke emissions test, which is primarily intended to identify vehicles that are in a very poor state of repair, whilst emitting illegal and harmful levels of fine exhaust particulate. It is an offence under the Road vehicles (Construction and Use) Regulations (Regulation 61a(3))1 to use a vehicle which has been modified in such a way that it no longer complies with the air pollutant emissions standards it was designed to meet.
Removal of a DPF will almost invariably contravene these requirements, making the vehicle illegal for road use. The potential penalties for failing to comply are fines of up to £1,000 for a car or £2,500 for a light goods vehicle.