2010 Toyota Camry Owners Manual - Page 461

5-2. Steps to take in an emergency STEP 4 After the hybrid system has cooled down, check the power control unit coolant level and inspect the cooling system for leaks. STEP 5 Add power control unit coolant if necessary. Water can be used in an emergency if power control unit coolant is unavailable. (→P. 450) Have the vehicle checked at the nearest Toyota dealer as soon as possible.