2023 TOYOTA PRIUS overheating

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
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