A pump group, for a cooling system of an operating group of a vehicle, preferably of the engine group, which extends relative to an axis (X-X) and comprises: i) an impeller rotatable about the axis (X-X); ii) a shaft, which extends along the axis (X-X), onto which the impeller is integrally mounted; iii) an electric motor comprising a rotor integrally mounted on the shaft and a stator which axially and circumferentially surrounds the rotor; iv) an electronic command board operatively connected to the electric motor; v) a pump body comprising, along the axis (X-X): - a first casing in which the impeller is housed in an impeller chamber; - a second casing in which the electric motor is housed in a motor chamber, wherein the first casing and the second casing are separated by a first separating wall, wherein the second casing comprises an intermediate tubular wall which extends parallel to the axis (X-X) positioned between the rotor and the stator, said intermediate tubular wall comprising a first end fluid-tightly engaging the first separating wall, and a second end (625") fluid-tightly engaging a second separating wall, so that a rotor chamber and a stator chamber mutually fluid-tightly separated are defined in the motor chamber; - a third casing in which the electronic command board is housed in a command chamber; wherein the command chamber and the stator chamber are separated by the second separating wall; and wherein the stator chamber contains an amount of oil which at least partially fills the stator chamber so that the stator is cooled by convection; wherein the pump group is characterized in that the command chamber contains an amount of oil which at least partially fills the command chamber so that the electronic command board is cooled by convection; and in that the second separating wall comprises a plurality of connection openings angularly equidistant, which fluidically connects the command chamber and the stator chamber and which are crossable by the oil present in the command chamber and in the stator chamber in both directions. i) an impeller rotatable about the axis (X-X); ii) a shaft, which extends along the axis (X-X), onto which the impeller is integrally mounted; iii) an electric motor comprising a rotor integrally mounted on the shaft and a stator which axially and circumferentially surrounds the rotor; iv) an electronic command board operatively connected to the electric motor; v) a pump body comprising, along the axis (X-X): - a first casing in which the impeller is housed in an impeller chamber; - a second casing in which the electric motor is housed in a motor chamber, wherein the first casing and the second casing are separated by a first separating wall, wherein the second casing comprises an intermediate tubular wall which extends parallel to the axis (X-X) positioned between the rotor and the stator, said intermediate tubular wall comprising a first end fluid-tightly engaging the first separating wall, and a second end (625") fluid-tightly engaging a second separating wall, so that a rotor chamber and a stator chamber mutually fluid-tightly separated are defined in the motor chamber; - a third casing in which the electronic command board is housed in a command chamber; - a first casing in which the impeller is housed in an impeller chamber; - a second casing in which the electric motor is housed in a motor chamber, wherein the first casing and the second casing are separated by a first separating wall, wherein the second casing comprises an intermediate tubular wall which extends parallel to the axis (X-X) positioned between the rotor and the stator, said intermediate tubular wall comprising a first end fluid-tightly engaging the first separating wall, and a second end (625") fluid-tightly engaging a second separating wall, so that a rotor chamber and a stator chamber mutually fluid-tightly separated are defined in the motor chamber; - a third casing in which the electronic command board is housed in a command chamber; wherein the command chamber and the stator chamber are separated by the second separating wall; and wherein the stator chamber contains an amount of oil which at least partially fills the stator chamber so that the stator is cooled by convection; wherein the pump group is characterized in that the command chamber contains an amount of oil which at least partially fills the command chamber so that the electronic command board is cooled by convection; and in that the second separating wall comprises a plurality of connection openings angularly equidistant, which fluidically connects the command chamber and the stator chamber and which are crossable by the oil present in the command chamber and in the stator chamber in both directions.