Car Warning Lights Explained -

What does the DPF warning light mean?



One of the many advantages of a modern vehicle is that is electronics are constantly monitoring how everything is working. The car’s computer will be able to flag up any potential issues before they become a bigger problem, saving you money and a potential breakdown. The car will let you know if something is wrong by illuminating a light on the dashboard, sometimes accompanied by a message on an information screen.

A common warning light you may see if you drive a diesel vehicle is for the Diesel Particulate Filter, known as a DPF for short. These devices have been fitted for more than 20 years, especially to larger vehicles such as vans and SUVs.

The warning light will look different according to the vehicle you are driving, but it will usually look like an exhaust pipe with dots or circles inside a box. If you are not sure what to look for, the experts at Eden will of course be happy to show you.

If this light comes on, you may be able to fix it yourself – but you mustn’t ignore it, or it may lead to more expensive damage. First, it’s important to understand what your DPF does and how it works.

The filter is designed to prevent the harmful soot from leaving your exhaust pipe and is vital to improving air quality for everyone. The emissions equipment will also be tested as part of your annual MoT test, so it’s essential to keep it working well.

Like any sort of cleaning device, the DPF will eventually become clogged or full and need to be cleaned itself. Luckily, it is designed to do this process automatically and you may not even notice. It does this by injecting fuel into the filter which increases the temperature inside the filter and burns off the soot. It will only do this when the car is travelling at a certain speed, which is usually above 40mph – you may spot cars on the motorway which suddenly produce a puff of sooty smoke from the exhaust as they go through the process.

Why does my DPF get blocked?

The problems can occur when you are doing a lot of short local journeys and the car isn’t getting above 40mph for a long enough period to allow the filter to get hot enough to clean itself.

This is why Eden’s experts would never recommend a diesel vehicle for drivers who do mainly local trips and rarely venture outside of town.

How can I fix it?

The best way to prevent a blockage and to keep your DPF running properly is to make sure you occasionally take your car on a run where it can get up to normal temperature and be travelling at more than 40-50mph for a longer period.

This may burn off the soot without the car needing to do anything more, but the engine’s computers may decide they need to help move things along by injecting fuel into the filter. You may notice a change in engine note as this happens. This is nothing to worry about, but the car may flash up a warning if the process is interrupted, for example if you stop driving halfway through the cycle.

What do I do if the light stays on?

If the DPF warning light stays on after you have tried driving for a while, it’s time to call the experts at Eden for advice. We will be able to diagnose the problem, get your car running properly and give you advice to prevent it happening again.



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