2011 Toyota Prius Owners Manual - Page 544

5-2. Steps to take in an emergency Warning message Details Indicates that the pre-collision system is not currently functional because the grille or the sensor is dirty. This message also appears when the pre-collision system is not functional due to overheating. Correction procedure Check the grille and the sensor and clean them if they are dirty. In case of overheating, the system will become functional once the system cools down. (If equipped) (Flashes) Indicates that the radar cruise control sensor is dirty or covered with ice. Clean the sensor. (If equipped) (Flashes) Indicates that the radar cruise control system is unable to judge vehicle-to-vehicle distance. If the windshield wipers are on, turn them off or set them to either the intermittent or the slow mode. (If equipped) 522 PRIUS_U (OM47685U) DVD