Toyota PRIUS Manual page 627

Start the hybrid system and turn the air conditioning system
STEP 6
on to check that the radiator cooling fans operate and to
check for coolant leaks from the radiator or hoses.
The fans operate when the air conditioning system is turned on
immediately after a cold start. Confirm that the fans are operating by
checking the fan sound and air flow. If it is difficult to check these,
turn the air conditioning system on and off repeatedly.
(The fans may not operate in freezing temperatures.)
If the fans are not operating:
STEP 7
Stop the hybrid system immediately and contact any autho-
rized Toyota dealer or repairer, or another duly qualified and
equipped professional.
If the fans are operating:
Have the vehicle inspected at the nearest any authorized
Toyota dealer or repairer, or another duly qualified and
equipped professional.
PRIUS PHV_OM_OM47831E_(EE)
5-2. Steps to take in an emergency
5
627