A method for controlling the activation of an electric machine in voltage control mode for an electrical network of a motor vehicle following a failure of a traction battery present in a traction network of the vehicle. The traction network includes the traction battery, the electric machine, an inverter and a DC-to-DC converter connecting the traction battery to an onboard network of said motor vehicle. The method includes a step of precharging capacitors present in the electrical network and a step of activating the electric machine in voltage control mode for the electrical network. The activation of the electric machine in voltage control mode is activated before the deactivation of precharging.