The invention relates to a maintenance system for an injector controlled by a solenoid actuator. The system comprises an electronic control unit arranged in a housing from which an electrical cable extends terminated by a special adapter capable of being connected onto the injector so that the injector is electrically connected with the electronic control unit while it remains in place on the internal combustion engine. The electronic control unit is designed for executing a plurality of operations according to a cycle of measurements including checking the electrical insulation, measuring the electrical resistance and measuring the electrical inductance of the solenoid and a solenoid activation test. The system is further provided with actuating means for starting the cycle and an information means for indicating data relating to the cycle in progress.