engine overheat TOYOTA PRIUS PRIME 2021 Owners Manual (in English)

17Pictorial index
PRIUS PRIME_OM_OM47D71U_(U)Fuel filler door . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 371
Refueling method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 371
Fuel type/fuel tank capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 732
Charging port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 110
Charging method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 134
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 614
Replacing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 629
Tire size/inflation pressure . . . . . . . . . . . . . . . . . . . . . . . . . P. 737
Winter tires/tire chain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 507
Checking/rotation/tire pressure warning system . . . . . . . . .P. 614
Coping with flat tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 692
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 597
Opening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 597
Engine oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 734
Coping with overheat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 721
Headlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 353
Parking lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 353
Fog lights
* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 363
LED accent lights
*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 353
Turn signal lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 351
Daytime running lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 353
Side marker lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 353
Tail lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 353
License plate lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 353
Back-up lights
Shifting the shift position to R . . . . . . . . . . . . . . . . . . . . . . . . . P. 345
5
6
7
8
Light bulbs of the exterior lights for driving
(Replacing method: P. 655, Watts: P. 738)
*: If equipped
9
10
11
12
13
14
15
16
17
18

208
PRIUS PRIME_OM_OM47D71U_(U)
3. Instrument cluster
■BSM (Blind Spot Monitor) outside rear view mirror indicators
(if equipped) (P. 432)
• When the BSM function is enabled on the screen of the multi-infor-
mation display, the power switch is turned to ON mode.
If the system is functioning correctly, the BSM outside rear view mirror indi-
cators will turn off after a few seconds.
If the BSM outside rear view mirror indicators do not illuminate or do not
turn off, there may be a malfunction in the system.
If this occurs, have the vehicle inspected by your Toyota dealer. ●Indicators are also displayed on the out-
side rear view mirrors.
●In order to confirm operation, the BSM
outside rear view mirror indicators illumi-
nate in the following situations:
• When the power switch is in ON
mode, the BSM function is enabled
on the screen of the multi-infor-
mation display.
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 your Toyota dealer
immediately 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. 721)

PRIUS PRIME_OM_OM47D71U_(U)
3255-1. Before driving
5
Driving
WARNING
Observe the following precautions.
Failure to do so may result in death or serious injury.
■When driving the vehicle
●Use engine braking (shift position B instead of shift position D) to maintain
a safe speed when driving down a steep hill.
Using the brakes continuously may cause the brakes to overheat and lose
effectiveness. (P. 346)
●Do not adjust the positions of the steering wheel, the seat, or the inside or
outside rear view mirrors while driving.
Doing so may result in a loss of vehicle control.
●Always check that all passengers’ arms, head or other parts of their body
are not outside the vehicle.
●Do not drive across river crossings or through other bodies of water.
This may cause electric/electronic components to short circuit, damage
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●Do not drive in excess of the speed limit. Even if the legal speed limit per-
mits it, do not drive over 85 mph (140 km/h) unless your vehicle has high-
speed capability tires. Driving over 85 mph (140 km/h) may result in tire
failure, loss of control and possible injury. Be sure to consult a tire dealer
to determine whether the tires on your vehicle are high-speed capability
tires or not before driving at such speeds.
■When driving on slippery road surfaces
●Sudden braking, acceleration and steering may cause tire slippage and
reduce your ability to control the vehicle.
●Sudden acceleration, engine braking due to shifting, or changes in engine
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●After driving through a puddle, depress the brake pedal to make sure that
the brakes are functioning properly. Wet brake pads may prevent the
brakes from functioning properly. If the brakes on only one side are wet
and not functioning properly, steering control may be affected.

PRIUS PRIME_OM_OM47D71U_(U)
3275-1. Before driving
5
Driving
WARNING
Observe the following precautions.
Failure to do so may result in death or serious injury.
■If you hear a squealing or scraping noise (brake pad wear limit indica-
tors)
Have the brake pads checked and replaced by your Toyota dealer as soon
as possible.
Rotor damage may result if the pads are not replaced when needed.
It is dangerous to drive the vehicle when the wear limits of the brake pads
and/or those of the brake discs are exceeded.
■When the vehicle is stopped
●Do not depress the accelerator pedal unnecessarily.
If the shift position is in any position other than P or N, the vehicle may
accelerate suddenly and unexpectedly, causing an accident.
●In order to prevent accidents due to the vehicle rolling away, always keep
depressing the brake pedal while stopped with the “READY” indicator is
illuminated, and apply the parking brake as necessary.
●If the vehicle is stopped on an incline, in order to prevent accidents caused
by the vehicle rolling forward or backward, always depress the brake pedal
and securely apply the parking brake as needed.
●Avoid revving or racing the engine.
Running the engine at high speed while the vehicle is stopped may cause
the exhaust system to overheat, which could result in a fire if combustible
material is nearby.

504
PRIUS PRIME_OM_OM47D71U_(U)
5-5. Using the driving support systems
■ECB operating sound
ECB operating sound may be heard in the following cases, but it does not
indicate that a malfunction has occurred.
●Operating sound heard from the engine compartment when the brake pedal
is operated.
●Motor sound of the brake system heard from the front part of the vehicle
when the driver’s door is opened.
●Operating sound heard from the engine compartment when one or two min-
utes passed after the stop of the hybrid system.
■EPS operation sound
When the steering wheel is operated, a motor sound (whirring sound) may be
heard. This does not indicate a malfunction.
■Automatic reactivation of TRAC and VSC systems
After turning the TRAC and VSC systems off, the systems will be automati-
cally re-enabled in the following situations:
●When the power switch is turned off
●If only the TRAC system is turned off, the TRAC will turn on when vehicle
speed increases
If both the TRAC and VSC systems are turned off, automatic re-enabling
will not occur when vehicle speed increases.
■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. 675

6898-2. Steps to take in an emergency
PRIUS PRIME_OM_OM47D71U_(U)
8
When trouble arises
■If “Shift to Before Exiting Vehicle” is shown
Message is displayed when the driver’s door is opened without turning the
power switch to off with the shift position in any position other than P.
Shift the shift position to P.
■If “Shift is in Release Accelerator Before Shifting” is shown
Message is displayed when the accelerator pedal has been depressed and
the shift position is in N.
Release the accelerator pedal and shift the shift position to D or R.
■If “Depress Brake When Vehicle is Stopped. Hybrid System may Over-
heat.” is shown
The message may be shown when the accelerator pedal is depressed to hold
the vehicle while the vehicle is stopped on an uphill, etc.
The hybrid system may overheat. Release the accelerator pedal and depress
the brake pedal.
■If “Shifted to Stop Vehicle to Shift to ” is shown
If the P position switch is pressed while driving, the shift position is changed
to N and the message is shown. (P. 347)
■If “Auto Power OFF to Conserve Battery” is shown
The power switch has been turned off by the automatic power off function.
When starting the hybrid system next time, operate the hybrid system for
approximately 5 minutes to recharge the 12-volt battery.
■If “Engine Oil Level Low Add or Replace” is displayed
The engine oil level may be low. Check the level of the engine oil, and add
engine oil if necessary. This message may be displayed if the vehicle is
stopped on a slope. Move the vehicle to a level surface and check if the mes-
sage disappears.
■If “Accelerator and Brake Pedals Pressed Simultaneously” is shown
The accelerator and brake pedals are being depressed simultaneously.
(P. 322)
Release the accelerator pedal and depress the brake pedal.
■If a message that indicates the malfunction of front camera is displayed
The following systems may be suspended until the problem shown in the
message is resolved. (P. 382, 674)
●PCS (Pre-Collision System)
●LTA (Lane Tracing Assist)
●AHB (Automatic High Beam)
●RSA (Road Sign Assist)
*
●Dynamic radar cruise control with full-speed range
*: If equipped

7248-2. Steps to take in an emergency
PRIUS PRIME_OM_OM47D71U_(U)
After stopping the hybrid system and waiting for 5 minutes or
more, start the hybrid system again and check if “Hybrid System
Overheated” 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:
The hybrid system temperature has dropped and the vehicle may
be driven normally.
However, if the message appears again frequently, contact your To y o t a
dealer.
WARNING
■To prevent an accident or injury when inspecting under the hood of
your vehicle
Observe the following precautions.
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03004400560003004500580055005100560011[
●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 “Accessory”,
“Ignition ON” or mileage display (P. 210) on the main display and the
“READY” indicator are off.
When the hybrid system is operating, the gasoline engine may automati-
cally start, or the cooling fans 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 caps while the hybrid system and radi-
ator are hot.
High temperature steam or coolant could spray out.
6

791Alphabetical index
PRIUS PRIME_OM_OM47D71U_(U)
Radar sensor ........................ 378
Seat belts .............................. 584
Water-repellent coating......... 577
Clock ......................................... 192
Adjustment ............................ 197
Coat hooks ............................... 566
Combination meter .................. 192
Clock adjustment .................. 197
Main display .......................... 209
Multi-information display ....... 220
Warning lights and
indicators ............................ 201
Condenser ................................ 606
Console box ............................. 545
Consumption screen ....... 265, 271
Coolant ..................................... 604
Capacity ................................ 735
Checking ............................... 604
Preparing and checking
before winter....................... 507
Cooling system ........................ 604
Engine overheating ............... 721
Hybrid system overheating ... 723
Cruise control
Dynamic radar cruise control
with full-speed range .......... 414
Cup holders.............................. 546
Curtain shield airbags ............... 36
Customizable features ............ 753
Daytime running light
system .................................... 356
Deck board ............................... 549
Defogger
Outside rear view
mirrors ........................ 516, 527
Rear window ................. 516, 527
Windshield .................... 515, 527Dimension ................................ 730
Dinghy towing.......................... 337
Display
BSM (Blind Spot Monitor) ..... 432
Drive information .................. 222
Dynamic radar cruise control
with full-speed range .......... 414
Energy monitor ..... 223, 262, 268
Head-up display.................... 253
Intuitive parking assist .......... 446
LTA (Lane Tracing Assist) .... 404
Main display.......................... 209
Multi-information display ....... 220
Parking Support Brake
function............................... 460
Pre-collision warning ............ 385
RSA (Road Sign Assist) ....... 411
S-APGS (Simple Advanced
Parking Guidance
System) .............................. 471
Warning messages ............... 684
Do-it-yourself maintenance .... 594
Door courtesy lights ............... 541
Location ................................ 541
Wattage ................................ 738
Doors ................................ 281, 287
Automatic door locking
and unlocking system......... 284
Back door ............................. 287
Door glasses......................... 314
Door lock .............................. 281
Open door warning buzzer ... 285
Open door warning light ....... 676
Outside rear view mirrors ..... 312
Rear door child-protectors .... 284
Side doors ............................ 281
Side windows........................ 314
D
*: Refer to “MULTIMEDIA OWNER’S MANUAL”.

793Alphabetical index
PRIUS PRIME_OM_OM47D71U_(U)
Engine
Accessory mode ................... 340
Compartment ........................ 600
Engine switch........................ 338
Exhaust gas precautions ........ 56
Hood ..................................... 597
How to start the hybrid
system ................................ 338
Identification number ............ 732
If the hybrid system will not
start .................................... 709
If your vehicle has to be
stopped in an emergency ... 665
Ignition switch (power
switch) ................................ 338
Overheating .......................... 721
Power switch......................... 338
Engine coolant ......................... 604
Capacity ................................ 735
Checking ............................... 604
Preparing and checking
before winter....................... 507
Engine oil ................................. 601
Capacity ................................ 734
Checking ............................... 601
Oil pressure warning light ..... 674
Preparing and checking
before winter....................... 507
Engine switch (power
switch) .................................... 338
Auto power off function ......... 340
Changing the power switch
modes................................. 340
If your vehicle has to be
stopped in an emergency ... 665
Starting the hybrid system .... 338EPS (Electronic Power
Steering) ................................ 502
Function ................................ 502
Warning light......................... 675
EV auto mode ............................ 87
EV driving range ...................... 108
EV mode ..................................... 87
EV/HV mode selection
switch ....................................... 90
Event data recorder (EDR)........ 11
Exhaust gas precautions .......... 56
Flat tire ..................................... 692
Floor mats .................................. 26
Fluid
Brake .................................... 737
Transmission ........................ 736
Washer ................................. 612
Fog lights ................................. 363
Replacing light bulbs ............ 660
Switch ................................... 363
Footwell lights ......................... 541
Front doors .............................. 281
Front fog lights ........................ 363
Replacing light bulbs ............ 660
Switch ................................... 363
Front passenger occupant
classification system .............. 50
Front passenger’s seat
belt reminder light................. 677
Front seat concentrated
airflow mode
(S-FLOW) ....................... 514, 526
F

795Alphabetical index
PRIUS PRIME_OM_OM47D71U_(U)
Hybrid battery (traction
battery) ..................................... 98
Air intake vent ......................... 99
Charging ............................... 110
Location .................................. 98
Specification ......................... 733
Status indicator ..................... 112
Hybrid battery (traction
battery) air intake vent ............ 99
Cleaning................................ 582
Hybrid system ............................ 86
Brake Override System......... 322
Consumption
screen................. 233, 265, 271
Drive-Start Control ................ 322
Emergency shut off system .... 99
Energy monitor ..... 223, 262, 268
High voltage components ....... 98
Hybrid System Indicator........ 225
If the hybrid system will not
start .................................... 709
Overheating .......................... 721
Plug-in hybrid system
precautions ........................... 98
Plug-in hybrid vehicle driving
tips ...................................... 105
Power switch......................... 338
Regenerative braking.............. 94
Starting the hybrid system .... 338
Vehicle proximity notification
system .................................. 93
Hybrid System Indicator ......... 225
Hybrid transmission ................ 345I/M test ...................................... 593
Identification ............................ 731
Engine .................................. 732
Vehicle .................................. 731
Ignition switch (power
switch).................................... 338
Auto power off function ......... 340
Changing the power switch
modes ................................ 340
If your vehicle has to be
stopped in an emergency ... 665
Starting the hybrid system .... 338
Illuminated entry system ........ 543
Immobilizer system ................... 83
Indicators ................................. 201
Initialization.............................. 765
Items to initialize ................... 765
Maintenance data ................. 588
Parking Support Brake
function............................... 464
Power windows..................... 315
S-APGS (Simple Advanced
Parking Guidance
System) .............................. 491
Tire pressure warning
system ................................ 616
Inside rear view mirror ............ 310
Instrument cluster light
control .................................... 194
Interior lights ........................... 541
Switch ........................... 542, 543
Wattage ................................ 738
Intuitive parking assist ........... 445I
*: Refer to “NAVIGATION SYSTEM OWNER’S MANUAL” or
“MULTIMEDIA OWNER’S MANUAL”.