Systems and methods for monitoring health of one or more subsystems of a vehicle system are disclosed. At least one sensor can be operatively coupled to a vehicle subsystem having an operational signature and a control system is coupled to the at least one sensor. Using information provided by the at least one sensor, the control system is structured to generate a reference signature of the subsystem during a learning phase and an operational signature of the subsystem subsequent to the learning phase. Systems and methods for identifying the particular subsystem exhibiting degraded performance are also disclosed.