1. A method for managing a power train of a motor vehicle, which is provided with an engine and an estimator of a temperature at a specific location of the engine, characterized in that it comprises a step of initialization of the estimator which is carried out when the power train starts, the initialization step comprising the following steps: determining a stop time of an element of the power train, determining at least one value which is representative of the temperature of the ambient air, evaluating a thermal parameter of the engine in accordance with the stop time determined and the determined value which is representative of the temperature of the ambient air, initializing the estimator based on the thermal parameter evaluated.