Diesel Particulate Filter Cleaning

Diesel vehicles can be prone to Diesel Particulate Filter (DPF) issues, the filter will block up making the vehicle go into ‘limp mode’ this is where the vehicle is constrained to a maximum speed of 40 mph, you will notice an immediate loss of power, very disconcerting if you are driving at the time and the engine management lights will all come on. Until you stop and restart your engine – do not ignore this!

One of the activities that can cause a blockage in the Diesel Particulate Filter (DPF) is ‘stop-start’ journeys with little or no motorway driving. Diesel vehicles fitted with Diesel Particle Filters for new emissions purposes, only operate and clean the particulate matter at around 70 mph in 4th or 5th gear at certain running temperatures. So when you are doing motorway miles will it clean out.

If you are using cheap fuels or the wrong grade oils, e.g. not using a low ash or saps oil where recommended. This can also cause the Diesel Particle Filter to block up. It will usually result in your mechanic needing to run a diagnostic to remedy the faults that may have caused the blockage, they will need to be rectified before this process can be carried out.

One of the problems with this system is when a vehicle is only doing short journeys, the engine may not get sufficiently hot to regen, so the deposits build up within the filter and a warning filter light comes on the dash, if the vehicle is then taken up to temp then it may be possible to force a regeneration and clear the filter but it doesn't totally clear and over time the part that isn't cleared by regen builds up and you have a totally blocked DPF and your vehicle may have a number of symptoms, limp mode, poor performance, poor MPG, engine management lights and in some cases the filter can be so blocked up the vehicle will not even start.