What is a DPF?
A diesel particulate filter (DPF) is a device designed to remove diesel particulate matter or soot from the exhaust gas of a diesel engine. It does this by trapping solid particles while letting gaseous components escape. All modern diesel cars are fitted with a DPF. It is important to maintain the DPF in good condition to prevent blockages as a they are very expensive to replace. A new one from a car manufacturer can cost anywhere between £1,000 and £3,500 and more depending on the make and model of the vehicle.
What is an EGR valve?
An EGR (Exhaust Gas Recirculation) system is a method to control harmful Nitrogen Oxides (NOx) emissions, produced as a by-product during the combustion process. The EGR system works by returning a small portion of exhaust gas to the engine’s combustion chambers through the intake manifold, lowering combustion temperatures and therefore reducing the amount of NOx emitted.
The EGR valve is the main component of the EGR system, and a frequent problem is sticking due to a buildup of carbon deposits. In worst cases, the EGR valve and EGR passages can be completely blocked and need replacing.