DPF-Diesel Particulate Filter What You Need to Know!

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A diesel particulate filter aka DPF collects and stores exhaust soot to reduce diesel vehicle emissions. The DPF filter must be frequently emptied and regenerated to prevent clogging or blocking. Regular maintenance is required.

Regeneration burns off the soot in the vehicle’s filter, reducing harmful emissions. This strategy eliminates the characteristic diesel giveaway—black smoke during acceleration—common before the 2000s.

Soot is burned off at high temperatures (approximately 600 degrees Celsius) to prepare the filter-to-filter additional particles. Diesel emissions harm human health and the environment. Diesel particulate filters became necessary in all EU diesel vehicles with 2009’s Euro 5 emission standards, which intended to cut CO2 emissions.

Since then, all diesel vehicles have diesel particulate filters, and half of all new cars sold are diesel. We installed a safety filter for diesel vehicles in your area. Toxic back smoke was minimized, and standards were applied.

DPF filter

DPF Blockage: Possible Causes

There are a variety of factors that might cause the filter to become clogged in any given vehicle and automobile engine. Factors such as the vehicle’s soot-release rate, low oil pressure, quality of fuel, driving habits, and the position of the particle filter can all play a role.

Filters in diesel vehicles become clogged and unable to properly renew for all the aforementioned reasons. When the regeneration process becomes troublesome or even doesn’t, most issues occur with vehicles making the rounds of the towns and cities.

In this instance, a diesel vehicle’s driver should keep an eye out for warning or flashing lights indicating that the DPF filter is not operating properly. If you keep driving in the same way, the soot will build up, and your car will enter a “limp mode” where you won’t be able to travel very fast.

The mechanic will need to perform a forced regeneration on the vehicle’s filter to clear out the soot that has accumulated there as a result of the filtration of acceleration. 

Even if you’re simply a car owner, you better familiarize yourself with the factors that can lead to a clogged DPF to be aware of regular maintenance.  Some typical triggers for a clogged DPF include:

  • Taking the diesel car out on short, frequent trips where it never gets out of the cold.
  • Use of subpar or incorrect engine oil.
  • Active regeneration ceases to take place when the fuel level is low, typically when it gets below 25% of the ideal level.
  • The use of Eolys additives may prevent regeneration
  • Excessive soot is produced due to a malfunction in the vehicle’s fuel system.

Diesel Particulate Filter Regeneration

DPF Active Regeneration

The DPF kicks regeneration in when the filter’s efficiency drops below a certain threshold, around 40%, and the exhausts are heated enough to burn off the accumulated soot.

The electronic control unit (ECU) of an automobile includes a regeneration mechanism that activates whenever additional gasoline is pumped automatically. When the filter reaches a certain percentage, it increases the temperature of the exhausts that burn the accumulated soot on the line. 

Short trips cause difficulties since regeneration cannot complete its cycle.  Whenever soot accumulates to the point that it stops the filter, a warning light should illuminate the control panel.

That could have been the time to choose a repair shop with the forced regeneration, as indicated by this indicator. However, the blockage can actually be minimized by the filter itself. The warning light should go out after about 10 minutes of driving at speeds over 50 mph. 

How to tell if your car has active regeneration and what the signs/symptoms are:

  • There’s a new sound coming from the engine.
  • There was a small rise in fuel use or mileage
  • Idle speed rises than usual
  • Exhaust gas is hot and has an acidic odor.
  • The air conditioners are on full blast.
  • The start and stop functions get disabled automatically.

DPF Passive Regeneration

Long, high-speed trips on the highway trigger passive regeneration, during which the vehicle’s exhaust temperatures rise to a point where any soot deposit in the filter is totally burned off.

Owners of diesel vehicles are encouraged to frequently subject their vehicles to half an hour of high-quality, steady highway driving in order to assist in clearing the filter.

The vast majority of motorist drivers, however, are not comfortable with such driving. That’s why the industry came up with a different method to achieve the goal.  

When The DPF Regeneration Doesn’t Work

Without a regeneration (whether it’s active or passive), a warning light will illuminate when the filter is completely clogged with soot. Checking the health of your car at this time is crucial and highly recommended.

The yellow emergency light will turn red and further DPF indicators will activate if the emergency light remains on. The car could sustain costly repairs if the warning indications are ignored so it needs to be handled immediately.

The concept of forced regeneration has become relevant at this point.  There is a high cost associated with forced regeneration because it must be performed in a workshop by a mechanic. In order to get your car to regenerate on its own again, you may need to “force” it by cleaning out any built-up soot in the garage.

Sometimes it’s not possible to force a regeneration to take place. A clogged filter prevents the vehicle from producing smoke, triggering limp mode. Some car models will continue to function normally even after being driven at 50-60 miles per hour.

temperature inside of a dpf


Soot is a byproduct of diesel combustion and is a known contributor to respiratory and cardiovascular illness. On the other hand, it’s one of the major pollutants that decrease the air quality and damage the environment.

Since the standards were applied, diesel particulate filters have been required in the exhaust systems of all new diesel automobiles to prevent harmful soot from entering the atmosphere. As a result, the majority of particle emissions from diesel automobiles were reduced.


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