N If Hybrid System Overheat is shown on the multiinformation display

stepQ Stop the vehicle in a safe place and turn off the air conditioning system.

STEp2 Leave the hybrid system operating and carefully lift the hood. Check if the cooling fans are operating. If the fans are operating: Wait until "HYBRID SYSTEM OVERHEAT" disappears and then stop the hybrid system.

If the message does not disappear, call your Toyota dealer. If the fans are not operating: Stop the hybrid system immediately and call your Toyota dealer.

After the hybrid system has cooled down, check the power control unit coolant level and inspect the cooling system for leaks.

Prius Coolant System

If necessary, add power control unit coolant up to the full line.

Water can be used in an emergency measure if power control unit coolant is unavailable. H-P. 562)

Have the vehicle checked at nearest Toyota dealer as soon as possible.

n Overheating

The following symptoms may occur when your vehicle is overheating: l Hybrid system output decrease. l Steam is coming from under the hood.


n To prevent an accident or injury when inspecting under the hood of your vehicle l If steam is seen coming from under the hood, do not open the hood until the steam has subsided. The engine compartment may be very hot, causing serious injury such as burns.

l With a hybrid vehicle, there are times when the gasoline engine automatically starts to run or the cooling fans suddenly start to operate. Do not touch or approach the rotating parts of the belt or fans. Doing so may lead to fingers, clothes or tools getting caught, resulting in an accidental injury.

l Do not loosen the coolant reservoir cap while the hybrid system and radiator are hot.

Serious injury, such as burns, may result from hot coolant and steam released under pressure.

a notice n When adding engine/power control unit coolant

Wait until the hybrid system has cooled down before adding engine/power control unit coolant.

When adding coolant, do so slowly. Adding cool coolant to a hot hybrid system too quickly can cause damage to the hybrid system.

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  • mary
    How to disable sos system in prius?
    9 years ago

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