Replace Diesel Particulate Filter (DPF)
Engine Light ON (or Service Engine Soon Warning Light)
The diesel exhaust aftertreatment system consists of an underhood pre-catalyst and an underbody catalyst. The underbody catalyst also consists of the main diesel oxidation catalyst and the coated Diesel Particulate Filter (DPF). One of the main purposes of the DPF is to collect particulates from the engine exhaust in order to minimize the discharge of soot to the atmosphere. The soot particles accumulate in the channels of the DPF and are burned off at regular intervals through a process called regeneration. This prevents the DPF from clogging. The Engine Control Module (ECM) commands the DPF regeneration after calculating various vehicle conditions such as DPF pressure difference, exhaust gas temperature, engine oil quality, engine speed, etc. Excessive accumulation of the soot in the DPF can cause a drop in the engine performance. During regeneration, additional fuel is injected via multiple post injections in order to increase the exhaust gas temperature. During this period, the DPF temperature is raised to approximately 600°C (1112°F) and the accumulated soot is oxidized or burned off into carbon dioxide (CO2).
The Diagnostic Trouble Code (DTC) will be set when the ECM detects that the exhaust gas temperature at exhaust gas temperature sensor 4 is greater than 900°C (1652°F) for greater than 12 s.