Abstract: A method is provided for checking engagement and disengagement of a parking brake finger, which selectively blocks or blocks a shaft of the transmission. A motor-driven rotary selection plate is selectively controlled to butt against the transmission casing at the two ends of its travel, and is immobilized therebetween in a first functional engagement position and in a second functional disengagement position that correspond to the Park and non Park positions of the parking brake finger when the drive motor of the plate stops exerting torque thereon. The angular movements of the plate between its abutment positions are measured and incremented using a computer to determine whether the engagement position and disengagement position of the plate that is reached every time the drive motor is stopped corresponds to a command instruction given to the motor.