Professional training: cleaning the diesel particulate filter

Vehicle & technology

Cleaning filters.

As a rule, the diesel particulate filter regenerates itself automatically. Only in exceptional circumstances does the driver need to initiate this process manually. Tips from professional trainer Peter Bodenseh.

The switch for diesel particulate filter regeneration (right): press the upper section to initiate manual regeneration or the lower section to activate or deactivate the regeneration lock. While the regeneration process is running, the symbol can also be seen lit up green in the AdBlue display.


The diesel particulate filter, which is part of the Mercedes-Benz truck exhaust after-treatment system, reduces particulate emissions to a virtually undetectable level. However, from time to time it is necessary to clean the filter and burn off the accumulated soot particles.

Regeneration of the diesel particulate filter is, as a rule, initiated automatically by the vehicle: depending on the vehicle use, between every 2000 and every 10 000 kilometres, whilst the vehicle is being driven. It commences when the particulate filter has reached a high load level, in other words a particular quantity of soot particles has accumulated in the filter. The only precondition for the process is that the engine is at operating temperature. The regeneration phase, which the driver is hardly aware of, takes between 30 and 60 minutes whilst the vehicle is in motion: it is only marked by a green indicator lamp that lights up on the AdBlue gauge. The driver does not need to intervene. When the regeneration process is completed, the indicator lamp goes out again.

If there are breaks or interruptions in the driving, the regeneration process stops and continues as soon as the truck gets moving again. The driver does not need to intervene.

If, for safety reasons, it should become necessary to interrupt the regeneration process due to the high exhaust gas temperature – for example at a chemical works, a refinery or when the truck is in operation at harvest time on freshly mown fields (see the Operating Instructions), simply press the OFF button on the switch. The regeneration process stops and the regeneration system is disabled. To enable the regeneration system again, press the OFF button again. Regeneration is then resumed while driving, and completed.

Manual regeneration can be necessary if a vehicle does not reach its full operating temperature due to short journeys. In this case, the system cannot initiate the regeneration process. The driver sees the display messages "Particulate filter Elevated fill level" and "Initiate regeneration" in the instrument cluster.

To do this, the driver should press the regeneration button for more than 3 seconds. The precondition is that the vehicle is stationary, with an adequately warm, idling engine, with the parking brake on, and Mercedes PowerShift is set to "Neutral". Here, too, regeneration takes about 30 to 60 minutes. Important: observe the safety regulations (Operating Instructions). Normally, the vehicle automatically initiates the regeneration process, thus combining maximum environmental protection with a high level of comfort for the drivers.

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