Page 332 of 492

3327-3. Do-it-yourself maintenance
YARIS_HV_EE_OM52F30E
■ If the coolant level drops within a short time of replenishing
Visually check the radiator, hoses, engine/power control unit coolant reservoir
caps, drain cock and water pump.
If you cannot find a leak, have any authorized Toyota dealer or repairer, or
another duly qualified and equipped professional, test the cap and check for
leaks in the cooling system.
Check the radiator and condenser and clear away any foreign objects.
If any of the above parts is extremely dirty or you are not sure of their
condition, have your vehicle inspected by any authorized Toyota
dealer or repairer, or another duly qualified and equipped profes-
sional.
WARNING
■ When the hybrid system is hot
Do not remove the engine/power control unit coolant reservoir caps.
The cooling system may be under pressure and may spray hot coolant if the
cap is removed, causing serious injuries, such as burns.
NOTICE
■ When adding coolant
Coolant is neither plain water nor stra ight antifreeze. The correct mixture of
water and antifreeze must be used to provide proper lubrication, corrosion
protection and cooling. Be sure to read the antifreeze or coolant label.
■ If you spill coolant
Be sure to wash it off with water to prevent it from damaging parts or paint.
Radiator and condenser
WARNING
■ When the hybrid system is hot
Do not touch the radiator or condenser as they may be hot and cause seri-
ous injuries, such as burns.
Page 395 of 492

3958-2. Steps to take in an emergency
8
When trouble arises
YARIS_HV_EE_OM52F30E
If you think something is wrong
●Fluid leaks under the vehicle
(Water dripping from the air conditioning after use is normal)
● Flat-looking tires or uneven tire wear
● High engine coolant temperature warning light flashes or comes on
● Changes in exhaust sound
● Excessive tire squeal when cornering
● Strange noises related to the suspension system
● Pinging or other noises related to the hybrid system
● Engine misfire, stumbling or running roughly
● Appreciable loss of power
● Vehicle pulls heavily to one side when braking
● Vehicle pulls heavily to one side when driving on a level road
● Loss of brake effectiveness, spongy feeling, pedal almost touches
the floor
If you notice any of the following symptoms, your vehicle proba-
bly needs adjustment or repair. Contact any authorized Toyota
dealer or repairer, or another duly qualified and equipped pro-
fessional as soon as possible.
Visible symptoms
Audible symptoms
Operational symptoms
Page 396 of 492

3968-2. Steps to take in an emergency
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If a war ning light tur ns on or a warning
buzzer sounds
Calmly perform the following actions if any of the warning lights
comes on or flashes. If a light comes on or flashes, but then
goes off, this does not necessarily indicate a malfunction in the
system. However, if this continues to occur, have the vehicle
inspected by any authorized Toyota dealer or repairer, or
another duly qualified and equipped professional.
Warning light and warning buzzer list
Warning lightWarning light/Details/Actions
(Red)
Brake system warning light (warning buzzer)*1
• Low brake fluid
• Malfunction in the brake system
This light also comes on when the parking brake is not
released. If the light turns off after the parking brake is fully
released, the system is operating normally.
→ Immediately stop the vehicle in a safe place and con-
tact any authorized Toyota dealer or repairer, or
another duly qualified and equipped professional.
Continuing to drive the vehicle may be dangerous.
Charging system warning light
Indicates a malfunction in the vehicle’s charging system.
→ Immediately stop the vehicle in a safe place and con-
tact any authorized Toyota dealer or repairer, or
another duly qualified and equipped professional.
Low engine oil pressure warning light
Indicates that the engine oil pressure is too low.
→ Immediately stop the vehicle in a safe place and con-
tact any authorized Toyota dealer or repairer, or
another duly qualified and equipped professional.
(Red warning light flashers or comes on)
High engine coolant temperature warning light
Indicates that the engine is overheating.
As the coolant temperature rises, it changes from flashing
to steady on.
→ P. 448
Page 448 of 492

4488-2. Steps to take in an emergency
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If your vehicle overheats
●The high engine coolant temperature warning light (→P. 396)
comes on or flashes, or a loss of hybrid system power is experi-
enced. (For example, the vehicle speed does not increase.)
● If the hybrid system overheat warning light (→P. 400) comes on.
● Steam comes out from under the hood.
■If the high engine coolant temperature warning light comes on
or flashes
Stop the vehicle in a safe place and turn off the air conditioning
system, and then stop the hybrid system.
If you see steam:
Carefully lift the hood after the steam subsides.
If you do not see steam:
Carefully lift the hood.
After the hybrid system has
cooled down sufficiently,
inspect the hoses and radia-
tor core (radiator) for any
leaks.
Radiator
Cooling fan
If a large amount of coolant
leaks, immediately contact any
authorized Toyota dealer or
repairer, or another duly quali-
fied and equipped professional.
The following may indicate that your vehicle is overheating:
Correction procedures
1
2
3
1
2
Page 449 of 492

4498-2. Steps to take in an emergency
8
When trouble arises
YARIS_HV_EE_OM52F30E
The coolant level is satisfac-
tory if it is between the
“FULL” and “LOW” lines on
the reservoir.
Reservoir
“FULL”
“LOW”
Add coolant if necessary.
Water can be used in an emer-
gency if coolant is unavailable.
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 condi tioning system is turned on immedi-
ately 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 condi-
tioning system on and off repeatedly.
(The fan may not operate in freezing temperatures.)
If the fan is not operating:
Stop the hybrid system immediately and contact any authorized
Toyota dealer or repairer, or another duly qualified and equipped
professional.
If the fan is operating:
Have the vehicle inspected at the nearest authorized Toyota
dealer or repairer, or another duly qualified and equipped profes-
sional.
4
1
2
3
5
6
7
Page 450 of 492
4508-2. Steps to take in an emergency
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■If the hybrid system overheat warning light comes on
Stop the vehicle in a safe place.
Stop the hybrid system and carefully lift the hood.
After the hybrid system has
cooled down, inspect the
hoses and radiator core
(radiator) for any leaks.
Radiator
Cooling fan
If a large amount of coolant
leaks, immediately contact any
authorized Toyota dealer or
repairer, or another duly quali-
fied and equipped professional.
The coolant level is satisfac-
tory if it is between the “F”
and “L” lines on the reservoir.
Reservoir
“F” line
“L” line
Add coolant if necessary.
Water can be used in an emer-
gency if coolant is unavailable.
1
2
3
1
2
4
1
2
3
5
Page 451 of 492

4518-2. Steps to take in an emergency
8
When trouble arises
YARIS_HV_EE_OM52F30E
Start the hybrid system and check for the hybrid system overheat
warning light.
If the warning light does not go off:
Stop the hybrid system and contact any authorized Toyota dealer or
repairer, or another duly qualified and equipped professional.
If the warning light goes off:
Have the vehicle inspected at the nearest authorized Toyota dealer
or repairer, or another duly qualified and equipped professional.
WARNING
■ To prevent an accident or injury when inspecting under the hood of
your vehicle
● 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, caus-
ing serious injuries such as burns.
● Check that the “READY” indicator is off.
● On hybrid vehicles, 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 fin-
gers 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 radia-
tor are hot.
Serious injuries, such as burns, may result from hot coolant and steam
released under pressure.
6
Page 452 of 492
4528-2. Steps to take in an emergency
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NOTICE
■ 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 sys-
tem too quickly can cause damage to the hybrid system.
■ 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 additives.