A common question amongst diesel vehicle owners is: "How long can I drive with the DPF light on?"

This blog will discuss all things Diesel Particulate Filters (DPF) including what can cause the DPF light to turn on, how long you can continue driving in this state, and what steps you should take if the DPF light comes on.

What is the DPF?

Diesel Particulate Matter (DPM) is the particles found in diesel engines that are responsible for the black smoke.

Diesel Particulate Filter (DPF) is a device designed to remove diesel particulate matter from the exhaust gas of a diesel engine and plays a vital role in the health and efficiency of the engine. ­It’s a device designed to remove diesel particulate matter from the exhaust gas of a diesel engine. In a nutshell, the DPF filter aids in minimising the emission of harmful pollutants, contributing to cleaner air and a healthier environment.

A DPF works much like a regular filter: by trapping and storing the soot particles produced during the engine's normal operation. After the DPF has gathered a certain number of particulates, it automatically burns them off, a process known as "regeneration."

Legislation introduced in 2009 to help lower car emissions made DPFs mandatory in all diesel vehicles.

What can cause the DPF light to turn on

When the DPF becomes clogged or blocked, an orange car warning light will appear on your car’s dashboard.

Primarily, the DPF light is designed to alert you when the DPF filter becomes too full of soot and can’t self-clean. This often happens when the vehicle is frequently driven for short distances or at low speeds, not allowing the DPF to reach the temperature required for a successful regeneration.

Additionally, a faulty DPF pressure sensor can also cause the light to illuminate. The DPF pressure sensor monitors the amount of soot in the filter, and if it malfunctions, it may incorrectly signal that the filter is full

Poor servicing and vehicle maintenance can also cause a DPF to become blocked. Generally, a DPF should last at least 100,000 miles if the vehicle is well serviced and looked after.

Book a your vehicle in for a service now on Caura to ensure your engine and all its parts are running efficiently.

How long can you drive with the DPF light on

The short answer is, not long.

Once the DPF light illuminates, it's a signal that your DPF filter is reaching its capacity and needs immediate attention. While your vehicle won't stop running the moment the light turns on, continuous driving can lead to more severe issues like decreased fuel efficiency, reduced performance, and in the worst case, engine damage.

An illuminated DPF light will cause an MOT failure. Since part of an MOT test is to check that vehicles comply to environmental standards, a faulty or missing DPF will cause an immediate failure.  

What to do if the DPF light comes on

If your DPF light turns on, the first thing you should do is attempt to initiate a DPF regeneration cycle.

This can be done by driving at a consistent speed of at least 40 mph for approximately 10 minutes. This higher sustained speed increases the exhaust temperature, which can often trigger a DPF regeneration.

However, if the DPF light remains on after trying this, or if it's constantly coming on, it's time to take your vehicle to a professional mechanic. They can perform a manual or forced DPF regeneration, or if needed, clean or replace the DPF filter.

Remember, prompt attention to a lit DPF light can save you from expensive repair costs and prolong the life of your vehicle.

Book into a garage near you on Caura today.

How to avoid future DPF problems

To avoid frequent DPF issues, follow these simple guidelines:

• Regularly drive your vehicle at higher (but legal!) speeds on a motorway for at least 20 minutes. This allows the engine to reach the temperature required for DPF regeneration
• Regularly service your vehicle, ensuring oil and filters are changed as per the manufacturer's guidelines
• Never ignore the DPF light. Take immediate action to prevent any long-term damage

Maintaining the health of your Diesel Particulate Filter (DPF) is not just about maintaining your vehicle's performance, it's also a matter of environmental responsibility. A well-functioning DPF filter reduces the emission of harmful pollutants, contributing to cleaner air and a healthier environment.

Stay on top of vehicle maintenance in Caura.