Toyota Prius: If your vehicle overheats

The following may indicate that your vehicle is overheating.

• The high coolant temperature warning light comes on or flashes, or a loss of hybrid system power is experienced. (For example, the vehicle speed does not increase.)
•  "Engine Coolant Temp High Stop in a Safe Place See Owner's Manual" or "Hybrid System Overheated Output Power Reduced" is shown on the multi-information display.
•  Steam comes out from under the hood.

Correction procedures

If the high coolant temperature warning light comes on or flashes or "Engine Coolant Temp High Stop in a Safe Place See Owner's Manual" is shown on the multi-information display

1. Stop the vehicle in a safe place and turn off the air conditioning system, and then stop the hybrid system.
2. If you see steam: Carefully lift the hood after the steam subsides.

   If you do not see steam: Carefully lift the hood.

3. After the hybrid system has cooled down sufficiently, inspect the hoses and radiator core (radiator) for any leaks.

1. Radiator
2. Cooling fans

If a large amount of coolant leaks, immediately contact your Toyota dealer.

4. The coolant level is satisfactory if it is between the "MAX" and "MIN" lines on the reservoir.

1. Reservoir
2. "MAX" line
3. "MIN" line

5. Add coolant if necessary.

Water can be used in an emergency if engine coolant is unavailable.

If water was added in an emergency, have the vehicle inspected at your Toyota dealer as soon as possible.

6. Start the hybrid system and turn the air conditioning system on to check that the radiator cooling fan operates and to check for coolant leaks from the radiator or hoses.

The fan operates when the air conditioning system is turned on immediately after a cold start. Confirm that the fan is 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 fan may not operate in freezing temperatures.)

7. If the fan is not operating: Stop the hybrid system immediately and contact your Toyota dealer.

   If the fan is operating: Have the vehicle inspected at the nearest Toyota dealer.

8. Check if "Engine Coolant Temp High Stop in a Safe Place See Owner's Manual" is shown on the multi-information display.

If the message does not disappear: Stop the hybrid system and contact your Toyota dealer.

If the message is not displayed: Have the vehicle inspected at the nearest Toyota dealer.

If "Hybrid System Overheated Output Power Reduced" is shown on the multi-information display

1. Stop the vehicle in a safe place.
2. Stop the hybrid system and carefully lift the hood.
3. After the hybrid system has cooled down, inspect the hoses and radiator core (radiator) for any leaks.

1. Radiator
2. Cooling fans

If a large amount of coolant leaks, immediately contact your Toyota dealer.

4. The coolant level is satisfactory if it is between the "F" and "L" lines on the reservoir.

1. Reservoir
2. "F" line
3. "L" line

5. Add coolant if necessary.

Water can be used in an emergency if power control unit coolant is unavailable.

If water was added in an emergency, have the vehicle inspected at your Toyota dealer as soon as possible.

6. After stopping the hybrid system and waiting for 5 minutes or more, start the hybrid system again and check for the multi-information display.

If the message does not disappear: Stop the hybrid system and contact your Toyota dealer.

If the message is not displayed:

The hybrid system temperature has dropped and the vehicle may be driven normally.

However, if the message appears again frequently, contact your Toyota dealer.

WARNING

When inspecting under the hood of your vehicle

Observe the following precautions.

Failure to do so may result in serious injury such as burns.

• 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.

• After the hybrid system has been turned off, check that the "READY" indicator is off.

  When the hybrid system is operating, the gasoline engine may automatically start, or the cooling fan may suddenly operate even if the gasoline engine stops. Do not touch or approach rotating parts such as the fan, which may lead to fingers or clothing (especially a tie, a scarf or a muffler) getting caught, resulting in serious injury.

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

  High temperature steam or coolant could spray out.

NOTICE

When adding engine/power control unit coolant

Add coolant slowly after the hybrid system has cooled down sufficiently. Adding cool coolant to a hot hybrid system too quickly can cause damage to the hybrid system.

NOTICE

To prevent damage to the cooling system

Observe the following precautions:

• Avoid contaminating the coolant with foreign matter (such as sand or dust, etc.).
• Do not use any coolant additive.