REFRIGERANT LOSS PROGNOSTIC STRATEGY FOR HEAT PUMPS OF VEHICLES

A motor vehicle includes a heat pump with an expansion valve and a controller that is configured to control a position of the expansion valve based, at least in part, on a superheat target, and utilize differences between an expected position of the expansion valve and a controlled position of the expansion valve to estimate a refrigerant level of the heat pump and/or a remaining useful life of the heat pump. The controller is optionally configured to determine a plurality of estimated refrigerant levels during closed loop control of the heat pump system and utilize the plurality of estimated refrigerant levels to determine a trend in refrigerant level over time.