How to Tell if Your DPF is Clogged

What Does my DPF Actually Do?

A DPF filter (Diesel Particulate Filter) is installed in your car to trap diesel particulate matter, also known as soot, in the exhaust system. This prevents your exhaust from polluting black fumes into the atmosphere. If there is black smoke leaving your exhaust pipe, this is an obvious indicator that your DPF filter is not working properly. Like any filter, your DPF will, over time, start to form a blockage from the waste that it holds and will need to be cleaned. 

DPF filters are built in such a way that allows them to clean themselves. When a car is driven at high speeds for an extended time, the engine will heat up to a degree that the DPF filter can burn away any excess soot. This process is called passive regeneration. As diesel cars are designed for this style of driving, this solution makes sense, in theory. However, not everyone who owns a diesel car has regular opportunities to drive like this, which results in the deposits of diesel matter clogging the filter. Aside from black smoke coming from the exhaust and the appearance of your DPF warning light, there are other ways to tell if your DPF is clogged. 



Blocked DPF Symptoms 

  • Reduced Fuel Economy

Your DPF filter is designed to conduct exhaust fumes out of the car’s engine, so when it is blocked, these fumes cannot leave the engine as quickly. This stops the engine from working to its full capacity and will invariably reduce your fuel efficiency. Not only will you be spending more on fuel, but the build up of fumes in your engine can cause severe damage to your engine.

  • Weaker Drive Feel

As a result of the engine not being able to work as efficiently as it could be, it cannot gather the same amount of power as it would normally. The buildup of fumes suffocates the engine, which makes your whole driving experience feel weaker. This in turn makes the diver be heavier on the gas, which burns through fuel quicker and contributes to the engine suffocation. What’s more, these fumes will smell, which is also a tell tale sign that your DPF filter is clogged.

  • Engine Refuses to Start

When your engine management unit detects the excess build up of fumes in your engine, it can refuse to start. This is for the safety of the engine, as the ignition process mixing with the fumes can cause major damage. While your engine not starting can be a major inconvenience, this is better than your engine sustaining potentially fatal damage.

DPF Regeneration

To combat the fact that many diesel car drivers are not driving in a way that allows passive DPF regeneration, many manufacturers have designed an active regeneration process. This takes place when the DPF filter reaches a certain point of gathered soot, and the ECU will provide a fuel injection into the engine to increase temperature. If the active regeneration process occurs during a short journey, and the engine is turned off before it can be completed, your DPF warning light will appear to tell you that the filter is partially blocked. 

So how do you tell that your engine is performing an active DPF regeneration? One signal to look for is your cooling fans running at a higher capacity than normal, or the sound of your engine may change note. Sometimes, a hot and pungent smell can also start coming from your engine as the soot is being burned away. Your stop / start function may also deactivate. Driving for 15 minutes as speeds above 40mph should provide your DPF filter with enough heat to burn away the soot by itself. 

If you ignore the tell tale signs of a DPF regeneration, your filter will become blocked and will need servicing professionally.

Our DPF Services

Here at DPF Solutions, we provide a wide range of services for clogged DPF filters. From forced regeneration to chemical cleaning, if you are experiencing blocked DPF symptoms, we can help you out. We have access to all the top Bosch diagnostic equipment to help us discern your car’s issue, along with our TerraClean DPF cleaning technology to perform top quality chemical purging. We are the top DPF specialists in Sheffield, so get in touch with us if you need help with your clogged DPF.