engine overheat TOYOTA PRIUS PRIME 2020 Owners Manual (in English)

17Pictorial index
PRIUS PRIME_OM_OM47C77U_(U)Fuel filler door . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 368
Refueling method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 368
Fuel type/fuel tank capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 720
Charging port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 110
Charging method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 134
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . P. 602
Replacing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 617
Tire size/inflation pressure . . . . . . . . . . . . . . . . . . . . . . . . . P. 725
Winter tires/tire chain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 495
Checking/rotation/tire pressur e warning system . . . . . . . . .P. 602
Coping with flat tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 680
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 585
Opening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 585
Engine oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 722
Coping with overheat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 709
Headlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 350
Parking lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 350
Fog lights
* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 360
LED accent lights
*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 350
Turn signal lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 348
Daytime running lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 350
Side marker lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 350
Tail lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 350
License plate lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 350
Back-up lights
Shifting the shift position to R . . . . . . . . . . . . . . . . . . . . . . . . . P. 342
5
6
7
8
Light bulbs of the exterior lights for driving
(Replacing method: P. 643, Watts: P. 726)
*: If equipped
9
10
11
12
13
14
15
16
17
18

208
PRIUS PRIME_OM_OM47C77U_(U)
3. Instrument cluster
■BSM (Blind Spot Monitor) outsid e rear view mirror indicators
(if equipped) ( P. 421)
• 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 vi ew mirror indi-
cators will turn off after a few seconds.
If the BSM outside rear view mirror indicators do not illuminat e or do not
turn off, there may be a malfunction in the system.
If this occurs, have the vehicle inspected by your Toyota deale r.
●
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 li ght 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 v ehicle in a
safe place, and check the engine after it has cooled completely. (P. 709)

PRIUS PRIME_OM_OM47C77U_(U)
3235-1. 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. 343)
● 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
the hybrid system or cause other serious damage to the vehicle.
● Do not drive in excess of the speed limit. Even if the legal sp eed limit per-
mits it, do not drive over 85 mph (140 km/h) unless your vehicl e has high-
speed capability tires. Driving over 85 mph (140 km/h) may resu lt 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 slippa ge and
reduce your ability to control the vehicle.
● Sudden acceleration, engine braking due to shifting, or changes in engine
speed could cause the vehicle to skid, resulting in an accident.
● 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 sid e are wet
and not functioning properly, steering control may be affected.

PRIUS PRIME_OM_OM47C77U_(U)
3255-1. 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 neede d.
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 ac cidents 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.

492
PRIUS PRIME_OM_OM47C77U_(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 brak e pedal
is operated.
● Motor sound of the brake system heard from the front part of th e vehicle
when the driver’s door is opened.
● Operating sound heard from the engine compartment when one or t wo min-
utes passed after the stop of the hybrid system.
■ EPS operation sound
When the steering wheel is operated, a motor sound (whirring so und) 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 wh en vehicle
speed increases
If both the TRAC and VSC systems are turned off, automatic re-e nabling
will not occur when vehicle speed increases.
■ Reduced effectiveness of the EPS system
The effectiveness of the EPS system is reduced to prevent the s ystem from
overheating when there is frequent steering input over an exten ded period of
time. The steering wheel may feel heavy as a result. Should thi s 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 wa rning light (warning buzzer)
P. 663

6778-2. Steps to take in an emergency
PRIUS PRIME_OM_OM47C77U_(U)
8
When trouble arises
■If “Shift to Before Exiting Vehicle” is shown
Message is displayed when the driver’s door is opened without t urning the
power switch to off with the shift position in any position oth er than P.
Shift the shift position to P.
■ If “Shift is in Release Accelerat or 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 Ov er-
heat.” is shown
The message may be shown when the accelerator pedal is depresse d to hold
the vehicle while the vehicle is stopped on an uphill, etc.
The hybrid system may overheat. Release the accelerator pedal a nd 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 po sition is changed
to N and the message is shown. ( P. 344)
■ 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 s ystem 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 che ck if the mes-
sage disappears.
■ If “Accelerator and Brake Pedals D epressed Simultaneously” is shown
The accelerator and brake pedals are being depressed simultaneo usly.
( P. 320)
Release the accelerator pedal and depress the brake pedal.
■ If “Front Camera Unavailable See Owner’s Manual” or “Front Came ra
Unavailable” is displayed.
The following systems may be suspended until the problem shown in the
message is resolved. ( P. 392, 662)
● PCS (Pre-Collision System)
● LDA (Lane Departure Alert with steering control)
● Dynamic radar cruise control with full-speed range
● Automatic High Beam

7128-2. Steps to take in an emergency
PRIUS PRIME_OM_OM47C77U_(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 d oes 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 Toyota
dealer.
WARNING
■ To prevent an accident or injury 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 ho od until
the steam has subsided. The engine compartment may be very hot.
● After the hybrid system has been turned off, check that the “Ac cessory”,
“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 au tomati-
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 syste m and radi-
ator are hot.
High temperature steam or coolant could spray out.
6

777Alphabetical index
PRIUS PRIME_OM_OM47C77U_(U)
Clock ......................................... 192Adjustment ............................ 197
Coat hooks ............................... 553
Combination meter .................. 192 Clock adjustment .................. 197
Main display .......................... 209
Multi-information display ....... 218
Warning lights and
indicators ............................ 201
Condenser ................................ 594
Console box ............................. 532
Consumption screen ....... 263, 269
Coolant ..................................... 592 Capacity ................................ 723
Checking ............................... 592
Preparing and checking before winter....................... 495
Cooling system ........................ 592 Engine overheating ............... 709
Hybrid system overheating ... 711
Cruise control Dynamic radar cruise control with full-speed range .......... 403
Cup holders.............................. 533
Curtain shield airbags ............... 36
Customizable features ............ 741
Daytime running light system .................................... 353
Deck board ............................... 536
Defogger Outside rear view
mirrors ........................ 504, 515
Rear window ................. 504, 515
Windshield .................... 504, 514 Dimension ................................ 718
Dinghy towing.......................... 335
Display
BSM (Blind Spot Monitor) ..... 421
Drive information .................. 220
Dynamic radar cruise control with full-speed range .......... 403
Energy monitor ..... 221, 260, 266
Head-up display.................... 251
Intuitive parking assist .......... 434
LDA (Lane Departure Alert
with steering control) .......... 397
Main display.......................... 209
Multi-information display ....... 218
Parking Support Brake function............................... 448
Pre-collision warning ............ 381
S-APGS (Simple Advanced
Parking Guidance
System) .............................. 459
Warning messages ............... 672
Do-it-yourself maintenance .... 582
Door courtesy lights ............... 528 Location ................................ 528
Wattage ................................ 726
Doors ................................ 279, 285 Automatic door locking
and unlocking system......... 282
Back door ............................. 285
Door glasses......................... 312
Door lock .............................. 279
Open door warning buzzer ... 283
Open door warning light ....... 664
Outside rear view mirrors ..... 310
Rear door child-protectors .... 282
Side doors ............................ 279
Side windows........................ 312
D
*: Refer to “MULTIMEDIA OWNER’S MANUAL”.

779Alphabetical index
PRIUS PRIME_OM_OM47C77U_(U)
EngineAccessory mode ................... 338
Compartment ........................ 588
Engine switch........................ 336
Exhaust gas precautions ........ 56
Hood ..................................... 585
How to start the hybrid system ......... ....................... 336
Identification number ............ 720
If the hybrid system will not start .................................... 697
If your vehicle has to be stopped in an emergency ... 653
Ignition switch (power
switch) ................................ 336
Overheating .......................... 709
Power switch......................... 336
Engine coolant ......................... 592 Capacity ................................ 723
Checking ............................... 592
Preparing and checking before winter....................... 495
Engine oil ................................. 589
Capacity ................................ 722
Checking ............................... 589
Oil pressure warning light ..... 662
Preparing and checking before winter....................... 495
Engine switch (power switch) .................................... 336
Auto power off function ......... 338
Changing the power switch modes................................. 338
If your vehicle has to be stopped in an emergency ... 653
Starting the hybrid system .... 336 EPS (Electronic Power
Steering) ................................ 490
Function ................................ 490
Warning light......................... 663
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 ..................................... 680
Floor mats .................................. 26
Fluid Brake .................................... 725
Transmission ........................ 724
Washer ................................. 600
Fog lights ................................. 360
Replacing light bulbs ............ 648
Switch ................................... 360
Footwell lights ......................... 528
Front doors .............................. 279
Front fog lights ........................ 360
Replacing light bulbs ............ 648
Switch ................................... 360
Front passenger occupant classification system .............. 50
Front passenger’s seat
belt reminder light................. 664
F

781Alphabetical index
PRIUS PRIME_OM_OM47C77U_(U)
Hybrid battery (traction battery) ..................................... 98
Air intake vent ......................... 99
Charging ............................... 110
Location .................................. 98
Specification ......................... 721
Status indicator ..................... 112
Hybrid battery (traction
battery) air intake vent ............ 99 Cleaning................................ 570
Hybrid system ............................ 86
Brake Override System......... 320
Consumption screen................. 231, 263, 269
Drive-Start Control ................ 320
Emergency shut off system .... 99
Energy monitor ..... 221, 260, 266
High voltage components ....... 98
Hybrid System Indicator........ 223
If the hybrid system will not start .................................... 697
Overheating .......................... 709
Plug-in hybrid system precautions ........................... 98
Plug-in hybrid vehicle driving tips ...................................... 105
Power switch......................... 336
Regenerative braking.............. 94
Starting the hybrid system .... 336
Vehicle proximity notification
system ......... ......................... 93
Hybrid System Indicator ......... 223
Hybrid transmission ................ 342 I/M test ...................................... 581
Identification ............................ 719
Engine .................................. 720
Vehicle .................................. 719
Ignition switch (power
switch).................................... 336 Auto power off function ......... 338
Changing the power switch modes ................................ 338
If your vehicle has to be stopped in an emergency ... 653
Starting the hybrid system .... 336
Illuminated entry system ........ 530
Immobilizer system ................... 83
Indicators ................................. 201
Initialization.............................. 752 Items to initialize ................... 752
Maintenance data ................. 576
Parking Support Brake function............................... 452
Power windows..................... 313
S-APGS (Simple Advanced Parking Guidance
System) .............................. 479
Tire pressure warning system .......... ...................... 604
Inside rear view mirror ............ 308
Instrument cluster light
control .................................... 194
Interior lights ........................... 528
Switch ........................... 529, 530
Wattage ................................ 726
Intuitive parking assist ........... 433I
*: Refer to “NAVIGATION SYSTEM OWNER’S MANUAL” or “MULTIMEDIA OWNER’S MANUAL”.