Warning lights can easily cause us to worry, but your DPF warning light can actually help you to avoid a major DPF replacement by making you aware of your exhaust’s increasing soot level.

Should you worry about your car’s diesel particulate filter warning light? Let’s find out.


My DPF Warning Light Is Illuminated

The sudden appearance of a light on your dashboard can be a stressful sight – particularly if you don’t know what that light signifies. Whilst an illuminated DPF warning light is most often an indication of a blocked DPF, it can sometimes be a sign instead of a faulty pressure sensor or even a temperature issue. It could also indicate a separate problem with your exhaust and injection system, or indeed be a signal that the wrong kind of oil is being used.

In order to determine the cause of the issue, and get your DPF working properly, you should take your car to a professional garage so that they can take a look and carry out high-quality DPF cleaning if needed.

DPF cleaning is certainly the smart choice, as a DPF replacement could cost you as much as £3000!


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Solid Light

The symbol for your DPF warning light usually looks like a little box with holes in it, as shown in the title image on this page - you can check your vehicle's handbook if you aren't certain. When this light comes on, it will shine yellow/amber to let you know that you are approaching maximum soot levels. This means that your vehicle needs to go through a process of regeneration in order to prevent the DPF from becoming blocked.

There are two types of regeneration that your car can go through in an attempt to unblock your DPF: active and passive.

Active regeneration is an automated process triggered by your car’s electronic control unit (ECU). Crucially, your car needs to be in motion long enough for this process to be completed, as your car has to reach a certain temperature – more fuel will automatically be sent to your exhaust in an attempt to raise the temperature during the regeneration process.

Passive regeneration can be instigated when you take your car on a longer drive, so that the exhaust has enough time to get to the correct temperature in order to burn off the excess soot. To make sure that the regeneration process has enough time to complete, you should drive at around 40 mph on the motorway for 15 minutes or more. Once the regeneration process is complete the light should hopefully go out, but you must give your DPF enough time at this higher temperature for the process to work.


Flashing Light

If your DPF warning light begins to flash, however, then this is a sign that the level of soot is extremely close to reaching full capacity. When your DPF is 70% full of soot, your car will enter ‘limp home’ mode, meaning your car’s performance will be restricted.

By the time your DPF is 90% full of soot, there will be little you can do to prevent the need for a full-on DPF replacement.


Can I Drive Whilst the DPF Warning Light Is On?

When you first notice your DPF warning light has come on, you should take your car for a drive on the motorway to trigger passive regeneration right away. If the warning light has been on for a while, then driving may just add to the level of soot that has already built up in your DPF. What’s more, if you keep driving then this could cause other warning lights on your dashboard to light up.

The best thing to do would be to book in for a professional DPF clean, before your car’s performance is limited any further. Do this every 6 to 9 months, and you can prevent the need for an expensive DPF replacement.

Once your DPF is functioning as it should, remember to take your diesel car out for longer drives regularly to activate the regeneration process.


How to Switch the DPF Warning Light Off

The easiest way to switch the DPF warning light off is to book a professional DPF clean at a garage near you.

When you want to do something about your vehicle’s increasing soot level, you can use BookMyGarage to book an appointment in just 3 steps. Prices start at £99, and this service includes a full inspection, diagnosis and flush, all performed by experienced and skilled mechanics.

Don’t ignore that warning light – book in for a DPF clean today!


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