An air suspension control system is for a vehicle with a first and a second axle. The system has an auxiliary control unit connected to a main control unit via a data link. The auxiliary unit has a pressure sensor associated with the first axle for determining pressure measurements of the first axle as pressure sensor signals and an input for receiving height sensor signals. The input can be connected to a first height sensor on the first axle for receiving first height signals and to a second height sensor on the second axle for receiving second height signals. The auxiliary unit is adapted to transmit the first and/or second height sensor signals and/or the pressure sensor signals to the main unit. The main unit is adapted to carry out weighing for the first and/or second axle in dependence on the first and/or second height signals and/or the pressure signals.