The invention concerns a system for assisting regeneration of pollution management means (1) associated with oxidation catalyst forming means implementing an oxygen storage capacity (OSC) function, and integrated in an exhaust line (3) of a motor vehicle diesel engine (4), wherein the engine is associated with common ramp means (7) supplying fuel to the cylinders thereof. The invention is characterized in that it comprises means (8) for determining the number of incomplete regeneration processes of the pollution management means and for comparing same to predetermined threshold values (10) to control the engine (4) in a first lean mixture regeneration operating mode (11) for a number less than the threshold values or in a second regeneration operating mode of engine operation sequences alternating rich mixture and lean mixture operating phases (12) for a number greater than the threshold values.