Diesel particulate filter warning light

Diesel particulate filter warning light

Often a source of misunderstandings dangerous to the health of your car, let's see what to do when the particulate filter light comes on.

FAP light: what it indicates

It may happen that the FAP light on the particulate filter appears on the dashboard of the car. To know how to behave in this case, it is necessary first of all to remember that the particulate filter serves to prevent the release into the atmosphere of particulate matter contained in the exhaust gases as a combustion product. The filter is constantly monitored by sensors that mainly measure the pressure difference created by filtration. When this difference is excessive, the electronic control and management control unit intervene by starting a process of self-cleaning and liberation through a regeneration cycle. If regeneration is not carried out appropriately and effectively, the FAP light of the particulate filter will light up to warn the driver of the anomaly. Most modern diesel cars are equipped with a particulate filter, but not everyone knows how to behave when the particulate light comes on the dashboard: do you have to stop right away? Let's go in order.

What to do if the FAP light is on?

The warning lamp indicates a fault in the particulate reduction system of the exhaust gas aftertreatment. In plain language, the exhaust gases of your own car are no longer optimally cleaned. If this message was caused, for example, by a defective sensor or a leak in a hose, you have no choice but to seek expert help. However, the message can also be caused by a saturation of the particulate filter. especially for diesel vehicles in frequent short-distance operations, a popular cause. If the vehicle has already switched to emergency mode to avoid further damage to the vehicle and the environment, the route to the workshop should be the first choice.
In this case, it is advisable to use the vehicle in such a way that the circumstances in which the regeneration cycle can take place are created, i.e., to proceed at the most constant engine speed possible at values of 2500–3000 rpm. To do this, you can travel on a suburban road and select the most useful gear to maintain the number of revolutions while respecting the speed limits. In this way, the control unit can intervene by increasing the amount of fuel introduced and, consequently, the temperature of the filter. The particulate matter, under these conditions, is reduced in size and the filter is released. We can say that, in principle, when the particulate filter light comes on, there is no need to be alarmed.

Do you know What is a Partial Filter? If not, this article is for you.

First of all, we remind you that the task of the particulate filter is to retain particulate matter from exhaust gases, preventing it from being released into the atmosphere.

Car manufacturers provide constant monitoring of the filter, which takes place with 2 sensors: they measure the difference in pressure upstream and downstream, and when this variation is too high, the control unit intervenes and starts a cleaning cycle (or regeneration).
The goal is to raise the temperature inside the filter up to about 550 °C, so as to incinerate the particulate matter and allow the unblocking of the FAP. When the so-called regeneration does not take place correctly, the light of the Particulate Filter lights up to warn you.

If the regeneration was successful, the fault lamp goes out. At the latest, at the next cold start. If it is not extinguished, one should consult an expert.