Page 354 of 512

3546-3. Do-it-yourself maintenance
AVALON_HV_U (OM41451U)
■Coolant selection
Only use “Toyota Super Long Life Coolant” or a similar high quality ethylene
glycol based non-silicate, non-amine, non-nitrite, and non-borate coolant with
long-life hybrid organic acid technology.
“Toyota Super Long Life Coolant” is a mixture of 50% coolant and 50% deion-
ized water. (Minimum temperature: -31 F [-35 C])
For more details about coolant, contact your Toyota dealer.
■ 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 your Toyota dealer test the cap and check for
leaks in the cooling system.
CAUTION
■When the hybrid system is hot
Do not remove the engine/power control unit coolant reservoir caps or the
radiator cap.( P. 447)
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 straight 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.
Page 382 of 512
3826-3. Do-it-yourself maintenance
AVALON_HV_U (OM41451U)■
Engine compartment (type A fuse box)
Fuse block
Fuse block on the back of the cover
Fuse layout and amperage ratings
FuseAmpereCircuit
1 METER-IG2 5 A Gauge and meters
2 FAN 50 A Electric cooling fans
3 H-LP CLN 30 A No circuit
4 ENG W/PMP 30 A Multiport fuel injection system/sequential
multiport fuel injection system
5 PTC HTR NO.2 50 A PTC heater
6 PTC HTR NO.1 50 A PTC heater
Page 385 of 512
3856-3. Do-it-yourself maintenance
6
Maintenance and care
AVALON_HV_U (OM41451U)■
Engine compartment (type B fuse box)
FuseAmpereCircuit
1 PM IGCT 7.5 A Hybrid system, electronic controlled
transmission
2 BATT VL SSR 10 A Hybrid system
3 INV 7.5 A Hybrid system
4 DC/DC IGCT 10 A Hybrid system
5 INV W/PMP RLY 7.5 A Hybrid system
6 BATT FAN 7.5 A Battery cooling fan
7 INV W/PMP 15 A Hybrid system
8 IGCT-MAIN 25 A DC/DC IGCT, INV, BATT VL SSR, PM
IGCT, INV W/PMP RLY, BATT FAN
Page 388 of 512

3886-3. Do-it-yourself maintenance
AVALON_HV_U (OM41451U)34 PANEL 10 A
Switch illumination, air conditioning sys-
tem, rear sunshade, seat heater, Blind
Spot Monitor, driving mode select switch,
steering wheel switch, ambient light, seat
ventilators, trunk opener switch, vehicle
stability control off switch, emergency
flashers, outside rear view mirrors, audio
system, navigation system
35 ECU-IG1 NO.1 10 A Electric cooling fans, steering sensor,
windshield wipers and washer, rear sun-
shade, seat heater, multiport fuel injec-
tion system/sequential multiport fuel
injection system, daytime running lights,
Blind Spot Monitor, charging system,
headlight (high beam), rear window
defogger, back up lights, outside rear
view mirror defoggers, fog lights, elec-
tronically controlled brake system, Vehi-
cle Proximity Notification System,
dynamic radar cruise control, pre-colli-
sion system
36 ECU-IG1 NO.2 10 A Shift lock control system, seat heaters,
seat ventilators, smart key system, tire
pressure warning system, wireless
remote control, multiplex communication
system, audio system, navigation sys-
tem, moon roof, auto anti-glare inside
rear view mirror, outside rear view mir-
rors, pre-collision system, dynamic radar
cruise control, air conditioning controls,
rain-sensing windshield wipers, starting
system
FuseAmpereCircuit
Page 444 of 512
4447-2. Steps to take in an emergency
AVALON_HV_U (OM41451U)
The engine coolant temperature gauge enters the red zone or a loss
of power is experienced. (For ex ample, the vehicle speed does not
increase.)
“Hybrid System Overheat/Stop the Vehicle in a Safe Place” is shown
on the multi-information display.
Steam comes out from under the hood.
■If the needle of the engine coolant temperature gauge enters
the red zone
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 your
Toyota dealer.
If your vehicle overheats
The following may indicate that your vehicle is overheating:
Correction procedures
1
2
3
1
2
Page 445 of 512

4457-2. Steps to take in an emergency
7
When trouble arises
AVALON_HV_U (OM41451U)
The coolant level is satisfac-
tory if it is between the “F”
and “L” lines on the reservoir.
Reservoir
“F” line
“L” line
Radiator cap
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 th e radiator or hoses.
The fan operates when the air conditioning 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 your Toyota
dealer.
If the fan is operating:
Have the vehicle inspected at the nearest Toyota dealer.
4
1
2
3
4
5
6
7
Page 446 of 512
4467-2. Steps to take in an emergency
AVALON_HV_U (OM41451U)■
If “Hybrid System Overheat/Stop the Vehicle in a Safe Place” is
shown on the multi-information display
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 your
Toyota dealer
The coolant level is satisfac-
tory if it is between the
“FULL” and “LOW” lines on
the reservoir.
Reservoir
“FULL” line
“LOW” line
Add coolant if necessary.
Water can be used in an emer-
gency if coolant is unavailable.
Start the hybrid system and chec k for the multi-information dis-
play.
If the message does not disappear:
Stop the hybrid system and contact your Toyota dealer.
If the message is not displayed:
Have the vehicle in spected at the nearest Toyota dealer.
1
2
3
1
2
4
1
2
3
5
6
Page 447 of 512

4477-2. Steps to take in an emergency
7
When trouble arises
AVALON_HV_U (OM41451U)
CAUTION
■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 indicator on the
“POWER” switch and the “READY” indicator are off.
When the hybrid system is operating, the gasoline engine may automati-
cally 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.
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.
■ 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.
●Do not loosen the radiator cap or the
coolant reservoir caps while the hybrid
system and radiator are hot.
High temperature steam or coolant
could spray out.