Diesel Particulate Filter Faults

A diesel particulate filter (DPF) is a device designed to remove diesel particulate matter or soot from the exhaust gas of a diesel engine.

Using information supplied by the differential pressure sensor the vehicle determines that the DPF is becoming full of soot and initiates the regeneration by injecting diesel post combustion. The diesel enters the exhaust and increases the temperature inside the DPF thus burning off the soot.

If a vehicle fails to regenerate the diesel particulate filter will become blocked and the engine management or DPF warning light will illuminate. The failure to regenerate can be caused by the style of driving or type of journeys covered not allowing the vehicle to reach the parameters required for regeneration or due to the failure of a sensor or component associated with the regeneration process.

It is paramount that the reason the original diesel particulate filter became blocked is correctly diagnosed and rectified prior to installation of a replacement unit. Once this has been done and the new unit fitted the vehicle must be set up correctly with compatible diagnostic equipment. Failure to set up the vehicle correctly after installation will almost certainly lead to the replacement DPF becoming blocked.

At JEM we have many years of experience working with vehicles with DPF problems and we have dealer level diagnostic equipment for almost every car on the road. We will correctly diagnose the cause of your DPF issue and supply you with a repair quotation. We have specialist equipment whereby we can either clean your existing DPF in situ or if it is too heavily blocked we can remove it from the vehicle and ultrasonically clean it prior to refitting and testing. If the DPF is damaged or completely plugged and therefore cannot be cleaned or cleaning is not economically viable we can replace it with a new part. We hold stock of all the fastest moving DPF’s in our parts department.

We do not remove diesel particulate filters and remap the ECU of vehicles as this is not legal. According to the DPF guidance sheet on the .GOV website it is an offence to remove the DPF filter.

Below is a copy of the relevant paragraph.

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.