2012 Toyota Prius Owners Manual - Page 850

5-2. Steps to take in an emergency STEP 3 Check to see if the cooling fans are operating. If the fans are operating: Wait until the high coolant temperature warning light goes off and then stop the hybrid system. If the fans are not operating: Stop the hybrid system immediately and call your Toyota dealer. STEP 4 After the hybrid system has cooled down sufficiently, check the engine coolant level and inspect the cooling system for leaks. STEP 5 If necessary, add engine coolant up to the "FULL" line. Water can be used in an emergency measure if engine coolant is unavailable. (→P. 566) ITO52P130 Have the vehicle checked at nearest Toyota dealer as soon as possible. 550