What is Forced Regeneration of the DPF filter?

• What is Forced Regeneration of the DPF filter?

Regeneration, or regen, of the DPF filter, is the process that burns the soot accumulation that is inside the DPF filter. Educating yourself on what forced regeneration is and how it works will help you understand your after-treatment system better.

Forced regeneration is performed when a diagnostic scan tool starts the regeneration process. The forced regeneration overrides the soot accumulation or soot levels that are calculated in the ECM. The DPF soot load could be too high for a passive and active regeneration to occur causing the condition where it is required to perform a forced regeneration. 

Forced regeneration is the highest level of the regeneration process and you will need a special diagnostic tool to start this process.

• If I replace a DPF Differential Pressure sensor or NOx Sensor, do I need to perform a regeneration?

Yes, some trucks do require you to perform a forced regeneration before it will clear certain fault codes. The reason is, is that the ECU wants to see that a forced regeneration is performed in order to clear the codes.

Example: 2013 Volvo D13 – SPN 4094 FMI 1 – SCR Conversion Efficiency low – A forced regeneration is required to clear this fault code. The measurement of PPM (parts per million) between the Inlet NOx 1 sensor & Outlet NOx 2 is out of range and causing this fault code. It’s recommended to check the EGR, and NOx Sensors, to make sure the PPM is within spec in order for this fault code will clear. The ECU will make this fault code go inactive ONLY when a forced regeneration passes with the values in the required range. This is an example where a fault code requires a forced regeneration.