Common Causes Of DPF Problems

The Diesel Particulate Filter (DPF) was first introduced in some vehicles from 2007 but became manditory in 2009 to meet Euro 5 emission regulations.


The DPF is used to filter the harmful soot from the combustion process, and stop them being released into the atmosphere. When the soot content reaches around 60% on most vehicles, the vehicle will attempt a passive regeneration when all conditions are correct.


The passive regeneration process happens as you drive along, most people dont even notice it, but some will notice a pulsing through the accelerator pedal. This process 'bakes' the soot content at a high temperature and turns it into smaller ash particles. If this process is interupted, then this leads to problems/fault lights.


When the soot content reaches 80%+ most vehicles will indicate a DPF light, glowplug light flashing, or message advising continuous driving required.


Theres two ways to proceed with this, a Dynamic Regen Or a Static Regen.


We always aim to carry out a Dynamic Regeneration first, this involves driving the vehicle at a set RPM, normally 3000-3500, for approx 20 minutes. We can do this easily on the dyno without having the hassle of traffic.


The second option is a Static Regen, which is commonly termed a 'Forced Regen', where we manually instruct the vehicle to carry out a regeneration in place.


If the soot content is high, the first job is to check if any codes are stored. This will indicate if there is a known concern preventing a passive/dynamic regen. Sensor faults are quite common, DPF pressure/temperature sensor faults being the most common.


Another reason for high soot content could be a sticking/faulty EGR valve. The EGR valves position is a condition for the DPF regen process to occur on many modern diesels, VAG group vehicles especially. People assume removing or 'deleting' the EGR will solve this issue, but typical software solutions do not work. The correct hysteresis maps need altered to allow the regen process to continue to occur.


We aim to return every vehicle back to factory working condition, which saves you the worry come MOT time.


The main reason people consider EGR / DPF deletes is because the factory replacement parts are so expensive. However, there is NO REASON TO EVER REPLACE THE DPF. The DPF is NEVER the problem.


Deleting the DPF is the go to solution for many garages that cant carry out diagnostics on modern vehicles.


If the DPF has been left to accumulate soot after continuous failed regeneration attempts, then there will come a point when the ecu will not allow a passive/dynamic/static regeneration. At this point, we would take your DPF off the vehicle, and send it to our partners at Ceramex who will remove the soot and ash content and bring the DPF back to as near new condition. We have successfully used their unique technology since 2014. More details here: DPF Cleaning


For those tuning vehicles with DPF's, we only recommend DPF removal at stage2+


For the majority of customers, DPF removal is not required.


If You Are Having DPF Problems... Drop Us A Message

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