DPF Warning Light

DPF Warning Lights, What you Need to Know

A diesel car will display a DPF warning light when there is a problem with the car’s diesel particulate filter. This filter reduces the amount of harmful soot emitted by the car and has been required, by law, to be fitted to all diesel cars since 2009.

A diesel car’s DPF can become blocked over time, causing a warning light to be displayed on the dashboard.

This needs to be addressed, as it reduces the amount of airflow the car has to expel exhaust gasses from the engine, which can cause a loss in power and eventually, other significant engine problems

How to Prevent a DPF Warning Light

Preventing a DPF warning light from ever showing is easy, the car simply needs to reach a temperature where the soot can be burnt away, which is most easily achieved by taking the diesel car for longer journeys and on the motorway.

To prevent a build-up of soot in the DPF, there are two types of regeneration that the car uses to burn it off:

Passive regeneration – This occurs as the car is running on long motorway journeys, allowing the exhaust to reach a high enough temperature to burn off the soot.

Active regeneration – This is fitted to diesel cars to help cope with drivers who often remain at low speeds. Automatically, the car will increase the amount of fuel it is using to increase the temperature of the exhaust, however, problems can occur if the journey is too short and the active regeneration does not have enough time to complete.

Diesel cars are not recommended for drivers who only remain local, but if you do often use the car in start-stop traffic or low speeds, then it is worth ensuring that you take the car for a longer motorway journey every month or so, to help burn off the soot build-up.

Can you Ignore a DPF Warning Light?

This depends on how significant the blockage is. The first thing you should do is take the car for a decent run along the motorway, this extended period of driving will heat up the temperature of the DPF and burn off some of the soot buildups. However, this is not the most reliable, or convenient method of cleaning the DPF and is not always effective, depending on how bad the blockage inside the DPF is.

However, this is not recommended, sometimes if you continue driving the soot might continue to build up, causing a fire hazard and will make the car to enter “limp mode”. Also, you cannot pass an MOT with a DPF warning light displaying on the dashboard, so make sure you address it as soon as possible.

If the light does not go off, or other warning lights appear, do not continue to drive the car.

What To Do If Your DPF Warning Light Comes On.

If your DPF warning light comes on, there is immediate no need to panic, like that of a check engine or ABS light.

In most cases, it is necessary to have the DPF filter professionally cleaned. This process will completely remove any build-up inside the DPF and make it perform like new. Increasing the amount of airflow the engine has, increasing performance.

Cleaning a DPF filter is much cheaper than replacing it with a new one. The nature of a DPF is to store soot, and as it can only be store a finite amount, it’s inevitable that the DPF light will eventually appear for cars that mostly drive around town or on smaller commutes.

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