Abstract: A method for monitoring a mechanical system for a vehicle. During an initial phase, measurements are taken of vibration values from vibration sensors and context parameters from context sensors in order to determine several values of a health indicator CI relating to the mechanical system and a variation model of a threshold relating to this health indicator CI and variable as a function of the context parameters. Next, during a monitoring phase, measurements are taken once more of vibration values and context parameters in order to determine an operational value of the health indicator CI and a threshold specific to this health indicator CI by means of the threshold variation model and the measured context parameters. A fault presence alarm may then be triggered if there is a risk of presence of a fault in the mechanical system.