overheating TOYOTA PRIUS 2023 Owners Manual

1162. Instrument cluster
PRIUS_OM_OM47F32E_(EE)
WARNING
■If a safety system warning light does not come on
Should a safety system light such as the ABS and SRS warning light not
come on when you start the hybrid system, this could mean that these sys-
tems are not available to help protect you in an accident, which could result
in death or serious injury. Have the vehicle inspected by any authorized
Toyota retailer or Toyota authorized repairer, or any reliable repairer imme-
diately if this occurs.
NOTICE
■ To prevent damage to the engine and its components
The engine may be overheating if the high coolant temperature warning
light comes on or flashes. In this case, immediately stop the vehicle in a
safe place, and check the engine after it has cooled completely. ( P. 645)

2284-1. Before driving
PRIUS_OM_OM47F32E_(EE)
WARNING
Observe the following precautions.
Failure to do so may result in death or serious injury.
■ When taking a nap in the vehicle
Always turn the hybrid system off. Otherwise, if you accidentally move the
shift lever or depress the accelerator pedal, this could cause an accident or
fire due to hybrid system overheating. Additionally, if the vehicle is parked in
a poorly ventilated area, exhaust gases may collect and enter the vehicle,
leading to death or a serious health hazard.
■ When braking
● When the brakes are wet, drive more cautiously.
Braking distance increases when the brakes are wet, and this may cause
one side of the vehicle to brake differently than the other side. Also, the
parking brake may not securely hold the vehicle.
● If the electronically controlled assist function does not operate, do not fol-
low other vehicles closely and avoid downhill or sharp turns that require
braking.
In this case, braking is still possible, but the brake pedal should be
depressed more firmly than usual. Also, the braking distance will increase.
Have your brakes fixed immediately.
● The brake system consists of 2 or more individual hydraulic systems; if
one of the systems fails, the other(s) will still operate. In this case, the
brake pedal should be depressed more firmly than usual and the braking
distance will increase. Have your brakes fixed immediately.
■ If the vehicle becomes stuck (AWD models)
Do not spin the wheels excessively when any of the tires is up in the air, or
the vehicle is stuck in sand, mud, etc. This may damage the driveline com-
ponents or propel the vehicle forward or backward, causing an accident.

2414-1. Before driving
4
Driving
PRIUS_OM_OM47F32E_(EE)■
Transmission information
To maintain engine braking efficiency and charging system perfor-
mance when using engine braking, do not use the transmission in
D. Shift the shift position to B.
■If the engine overheats
Towing a loaded trailer up a long, steep incline in temperatures
exceeding 30C (85F) may result in the engine overheating. If the
engine coolant temperature gauge indicates that the engine is over-
heating, turn the air conditioning off immediately, leave the road and
stop the vehicle in a safe place. (P. 645)
■When parking the vehicle
Always place wheel chocks under the wheels of both the vehicle
and trailer. Firmly set the parking brake and shift the shift position to
P.

2424-1. Before driving
PRIUS_OM_OM47F32E_(EE)
WARNING
Follow all the instructions described in this section.
Failure to do so could cause an accident resulting in death or serious injury.
■ Trailer towing precautions
When towing, make sure that none of the weight limits are exceeded.
( P. 2 3 4 )
■ To avoid accident or injury
● Vehicles with a compact spare tire:
Do not tow a trailer when the compact spare tire is installed on your vehi-
cle.
● Vehicles with the emergency tire puncture repair kit:
Do not tow a trailer when the tire installed is repaired with the emergency
tire puncture repair kit.
● Do not use cruise control or dynamic radar cruise control with full-speed
range when trailer towing. (if equipped)
■ Vehicle speed in towing
Observe the legal maximum speeds for trailer towing.
■ Before descending hills or long declines
Reduce speed and downshift. However, never downshift suddenly while
descending steep or long downhill grades.
■ Operation of the brake pedal
Do not hold the brake pedal depressed often or for long periods of time.
Doing so may result in the brake overheating or reduce braking effects.
NOTICE
■ Do not directly splice trailer lights
Directly splicing trailer lights may damage your vehicle’s electrical system
and cause a malfunction.

2604-2. Driving procedures
PRIUS_OM_OM47F32E_(EE)
Parking brake
To set the parking brake, fully
depress the parking brake pedal
with your left foot while depress-
ing the brake pedal with your right
foot.
(Depressing the pedal again
releases the parking brake.)
■ Parking the vehicle
 P. 220
■ Parking brake engaged warning buzzer
A buzzer will sound if the vehicle is driven with the parking brake engaged.
“Release Parking Brake” is displayed on the multi-information display (with
the vehicle reached a speed of 5 km/h [3 mph]).
■ Usage in winter time
 P. 453
Operating instructions
NOTICE
■Before driving
Fully release the parking brake.
Driving the vehicle with the parking brake set will lead to brake components
overheating, which may affect braking performance and increase brake
wear.

4454-5. Using the driving support systems
4
Driving
PRIUS_OM_OM47F32E_(EE)■Automatic reactivation of TRC and VSC systems
After turning the TRC and VSC systems off, the systems will be automatically
re-enabled in the following situations:
●When the power switch is turned off
●If only the TRC system is turned off, the TRC will turn on when vehicle
speed increases
If both the TRC and VSC systems are turned off, automatic re-enabling will
not occur when vehicle speed increases.
■Operating conditions of Active Cornering Assist
The system operates when the following occurs.
●TRC/VSC can operate
●The driver is attempting to accelerate while turning
●The system detects that the vehicle is drifting to the outer side
●The brake pedal is released
■Reduced effectiveness of the EPS system
The effectiveness of the EPS system is reduced to prevent the system from
overheating when there is frequent steering input over an extended period of
time. The steering wheel may feel heavy as a result. Should this occur, refrain
from excessive steering input or stop the vehicle and turn the hybrid system
off. The EPS system should return to normal within 10 minutes.
■Electric power steering system warning light (warning buzzer)
P. 581
■Operating conditions of emergency brake signal
When the following conditions are met, the emergency brake signal will oper-
ate:
●The emergency flashers are off.
●Actual vehicle speed is over 55 km/h (35 mph).
●The system judges from the vehicle deceleration that it is a sudden braking
operation.
■Automatic system cancelation of emergency brake signal
The emergency brake signal will be canceled in any of the following situa-
tions:
●The emergency flashers are turned on.
●The system judges from the vehicle deceleration that is not a sudden brak-
ing operation.

4685-1. Using the air conditioning system and defogger
PRIUS_OM_OM47F32E_(EE)
Seat heaters
: If equipped
Seat heaters heat the front seats.
WARNING
●Care should be taken to prevent injury if anyone in the following categories
comes in contact with the seats when the heater is on:
• Babies, small children, the elderly, the sick and the physically chal-
lenged
• Persons with sensitive skin
• Persons who are fatigued
• Persons who have taken alcohol or drugs that induce sleep (sleeping
drugs, cold remedies, etc.)
● Observe the following precautions to prevent minor burns or overheating:
• Do not cover the seat with a blanket or cushion when using the seat
heater.
• Do not use seat heater more than necessary.
NOTICE
● Do not put heavy objects that have an uneven surface on the seat and do
not stick sharp objects (needles, nails, etc.) into the seat.
● To prevent 12-volt battery discharge, do not use the functions when the
hybrid system is off.

6457-2. Steps to take in an emergency
PRIUS_OM_OM47F32E_(EE)
7
When trouble arises
If your vehicle overheats
■If the high 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 radiator core (radiator) for any leaks.
Radiator
Cooling fans
If a large amount of coolant
leaks, immediately contact
any authorized Toyota retailer
or Toyota authorized repairer,
or any reliable repairer.
The following may indicate that your vehicle is overheating.
● The high coolant temperature warning light (P. 583) comes on
or flashes, or a loss of hybrid system power is experienced. (For
example, the vehicle speed does not increase.)
● “Hybrid System Overheated” is shown on the multi-information
display.
● Steam comes out from under the hood.
Correction procedures
1
2
3
1
2

688Alphabetical index
PRIUS_OM_OM47F32E_(EE)
Care ................................... 496, 502
Aluminum wheels .................. 497
Exterior.................................. 496
Front camera......................... 285
Interior ................................... 502
Radar sensor ........................ 284
Seat belts .............................. 503
Water-repellent coating ......... 497
Cargo hooks ............................. 480
Catch protection function ....... 211
Chains ....................................... 453
Child restraint system ............... 54
Child restraint system
installation method................ 67
Fixed with a seat belt .............. 68
Fixed with an ISOFIX lower
anchorage............................. 70
Points to remember................. 54
Riding with children ................. 53
Using a top tether
anchorage............................. 72
Child safety ................................ 53
12-volt battery precautions.... 524
Airbag precautions .................. 41
Back door precautions .......... 184
Child restraint system ............. 54
How your child should wear
the seat belt .......................... 36
Installing child restraints.......... 67
Moon roof precautions .......... 218
Power window lock switch .... 210
Power window precautions ... 213
Rear door child-protectors .... 180
Removed key battery
precautions ......................... 556
Riding with children ................. 53
Seat belt precautions .............. 69
Seat heater precautions ........ 468Child-protectors....................... 180
Cleaning ........................... 496, 502
Aluminum wheels.................. 497
Exterior ................................. 496
Front camera ........................ 285
Hybrid battery (traction
battery) air intake vent ........ 545
Interior................................... 502
Radar sensor ........................ 284
Seat belts .............................. 503
Water-repellent coating......... 497
Clock ......................................... 100
Adjustment ............................ 106
Coat hooks ............................... 493
Combination meter .................. 100
Clock adjustment .................. 106
Main display .......................... 117
Multi-information display ....... 127
Warning lights and
indicators ............................ 110
Condenser ................................ 520
Console box ............................. 474
Coolant ..................................... 518
Capacity ................................ 662
Checking ............................... 518
Preparing and checking
before winter....................... 452
Cooling system ........................ 518
Engine overheating ............... 645
Hybrid system overheating ... 647
Consumption screen ............... 166
Cruise control
Cruise control........................ 346
Dynamic radar cruise control
with full-speed range .......... 329
Cup holders.............................. 475
Curtain shield airbags ............... 39
Customizable features ............ 670
C

690Alphabetical index
PRIUS_OM_OM47F32E_(EE)
ECB (Electronically
Controlled Brake System) .... 441
Eco drive mode ........................ 351
Electric motor (traction motor)
Location .................................. 79
Specification.......................... 657
Electric Power Steering
(EPS) ....................................... 442
Function ................................ 442
Warning light ......................... 581
Electronic key .......................... 172
Battery-saving function ......... 189
If the electronic key does not
operate properly ................. 636
Replacing the battery ............ 554
Electronically Controlled
Brake System (ECB).............. 441
Emergency brake signal ......... 442
Emergency flashers................. 568
Emergency brake signal ....... 442
Emergency tire puncture
repair kit ................................. 602
Emergency, in case of
If a warning buzzer sounds ... 580
If a warning light turns on ...... 580
If a warning message is
displayed ............................ 589
If the 12-volt battery is
discharged .......................... 639
If the electronic key does not
operate properly ................. 636
If the hybrid system will not
start..................................... 634
If the vehicle becomes
stuck ................................... 650
If the vehicle is submerged or
water on the road is
rising ................................... 570If you have a flat tire ..... 598, 618
If you lose your keys ..... 173, 176
If you think something is
wrong.................................. 579
If your vehicle has to be
stopped in an emergency ... 569
If your vehicle needs to be
towed .................................. 572
If your vehicle overheats ....... 645
Energy monitor ................ 130, 166
Engine....................................... 656
Accessory mode ................... 246
Compartment ........................ 514
Engine switch (power
switch) ................................ 244
Exhaust gas precautions ........ 50
Hood ..................................... 511
How to start the hybrid
system ................................ 244
Identification number ............ 656
If the hybrid system will not
start .................................... 634
If your vehicle has to be
stopped in an emergency ... 569
Ignition switch (power
switch) ................................ 244
Overheating .......................... 645
Power switch......................... 244
Engine coolant ......................... 518
Capacity ................................ 662
Checking ............................... 518
Preparing and checking
before winter....................... 452
E