FOREIGN SUBSTANCE DETECTION SYSTEM

A foreign substance detection system is disclosed to detect whether foreign substances are attached to an environmental sensor of a vehicle. The foreign substance detection system includes a detection loop through which current selectively flows. In particular, the detection loop includes a controller configured to operatively control a sensor cleaning system configured to clean an environmental sensor of a vehicle, and a power supply unit configured to continuously supply electric power to the controller. The environmental sensor includes a detection device configured to open or close the detection loop on the basis of whether a fluid or a foreign substance is attached.