Abstract: The invention relates to a system for managing a reagent dispensing device in the exhaust line of an engine, said circuit including a tank (1), an injection means (3), a means for conditioning the reagent, sensors capable of determining the representative parameters of the condition of the dispensing circuit and of the reagent, and actuators for controlling the conditioning and injection means driven by a calculation unit based on the condition of the dispensing circuit and of the reagent and on the engine parameters determined by an engine control unit (5) characterised in that the calculation unit is integrated in the engine control unit (5) and in that the system includes an analog/digital interface (4) for processing the analog signals from the sensors (2) and the actuators (3, 7, 8, 9), provided in the vicinity of the tank (1) and connected to the engine control unit by a multiplexed digital link.