SCR system (overall tank system): Notes

In contrast to the active tank, the passive tank has no heating to heat the carbamide-water mixture. There is also a different fill level sensor. The fill level detection in the passive tank takes place by means of two individual sensors that are fitted on the top and bottom of the passive tank. This means it is possible to detect a full tank. It is also possible to detect an empty tank. The exact fill level cannot be read out. The interplay between the passive tank and active tank is illustrated in the following illustration. The blending pump unit between the active tank and passive tank delivers the mixture. The primary pumping direction is from the passive tank to the active tank.