The dashboard of a modern car can be like a Christmas tree with the number of warning lights that can sometimes flash up when you turn the car on.
These lights can differ depending on the manner of propulsion, making it even trickier to know what each light means.
A common illumination in diesel cars is the DPF warning light, but what exactly does it mean, and how can this warning light be rectified? In this blog, we’re going to explain everything you need to know about DPF warning lights, what they mean, and whether you can drive with this light on your instrument cluster.
What is a DPF warning light?
A DPF warning light is a warning light that illuminates to signal that the DPF is blocked or full.
A diesel particulate filter, or DPF, is a device that filters out particulates from the exhaust of a diesel vehicle. All modern diesel vehicles have these filters fitted to them as standard, and help to reduce harmful emissions.
A DPF warning light is an orange light on your instrument cluster, that may look like an exhaust pipe with dots or circles inside a box, or a small engine icon with smoke blowing out of it.
What can cause a DPF warning light?
When the DPF gets full, the car’s computer runs a regeneration cycle which can temporarily increase fuel consumption, increase idling speed, and cause sour-smelling exhaust fumes.
For this to be completed, the engine needs reach a high enough temperature for a long enough time. If a driver is only completing short journeys, the regeneration cycle can’t be completed which, over time, can lead to the DPF becoming full or blocked leading to the DPF warning light will illuminate.
It’s advised to complete long journeys at high revs (exceeding 2,500rpm) regularly to ensure that your car or van’s DPF filter is being cleared consistently.
How to tell if my DPF is blocked
There are a few ways that you can tell your DPF is blocked.
The first obvious sign is usually the warning light, giving you a clear visual indicator that something isn’t right. You may also notice a reduction in engine power, darker, smelly exhaust smoke, and reduced fuel economy.
Other more subtle signs include cooling fans spinning faster, and the start/stop function stopping working.
Can you drive with a DPF warning light on?
When the DPF light is on, it is possible to still continue to drive the vehicle but you should adjust your driving to try and rectify the problem before it becomes unfixable.
A short blast on the motorway for about 10 to 20 minutes should fix the problem if you act swiftly enough. If the light doesn’t go out after that, it’s worth asking a mechanic to take a look to determine if there’s a more significant issue at hand.
If you continue to ignore the warning on your dashboard, then over time it can lead to engine problems or a broken DPF, which can range from a few hundred pounds up to a couple of thousand.
Can a blocked DPF fail an MOT?
A blocked DPF will indeed cause an MOT failure. A blockage in the DPF will mean that harmful particulates aren’t being taken out before they’re sent out the exhaust pipe.
During an MOT, the examiner will test a car’s emission levels to make sure they meet regulations. A blocked diesel particulate filter can cause an immediate MOT failure. The DPF warning light itself will not cause a failure, but it can be a sign that it’s likely to.
How to prevent a DPF warning light
If you want to make sure that your diesel car will pass its MOT, you can follow a few easy steps so that the DPF isn’t causing you, or your wallet, any issues.
Use the correct engine oil
Using poor-quality engine oil can lead to more ash and debris being put through the DPF. Over time, this can put unnecessary stress on the DPF and will mean that you will have to clear it more.
Regular drives
As mentioned earlier, a simple way to ensure that your DPF filter doesn’t become blocked is to regularly drive at speeds exceeding 40mph for more than 10 minutes, such as on the motorway.
Use a DPF cleaner
Using a high-quality DPF cleaner like Redex DPF Cleaner can help to clear the diesel particulate filter more effectively by reducing the temperature at which the regeneration cycle will begin. This is ideal for those who aren’t regular motorway drivers.
How to clear a DPF warning light
When you see any warning light appear on your dash, it can set alarm bells ringing in your head, but thankfully, the DPF warning light is a simple warning light to clear.
Clearing this light is usually as simple as taking your car for a short drive (between 10 and 15 minutes) at speeds exceeding 40 miles per hour.
Using a DPF cleaner can help to reduce this time or speed by lowering the temperature needed for the regeneration cycle to begin, helping to reduce the chances that serious damage will be caused to your DPF.
The DPF is absolutely crucial to the health of your diesel car, but also to the health of the planet by reducing the harmful emissions that come out of the back of your diesel car.
By following our tips, you can be sure that your DPF will be working properly for many miles to come.
For more quality products that will help the longevity of your car, take a look at our range of high-quality car maintenance products.
