2023 TOYOTA SIENNA HYBRID engine overheat

3384-5. Using the driving support systems
■Sounds and vibrations caused
by the ABS, brake assist, VSC,
TRAC, Trailer Sway Control and
hill-start assist control systems
●A sound may be heard from the
engine compartment when the
brake pedal is dep ressed repeat-
edly, when the hybrid system is
started or just after the vehicle
begins to move. This sound does
not indicate that a malfunction has
occurred in any of these systems.
●Any of the following conditions
may occur when t he above sys-
tems are operating. None of these
indicates that a malfunction has
occurred.
• Vibrations may be felt through the vehicle body and steering.
• A motor sound may be heard also after the vehicle comes to a stop.
■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 minutes passed after the stop
of the hybrid system.
■Active Cornering Assist opera-
tion sounds and vibrations
When the Active Cornering Assist is
operated, operation sounds and
vibrations may b e generated from
the brake system, but this is not a
malfunction.
■EPS operation sound
When the steering wheel is oper-
ated, a motor sou nd (whirring
sound) may be heard. This does not
indicate a malfunction.
■Automatic reactivation of
TRAC, Trailer Sway Control and
VSC systems
After turning the TRAC, Trailer
Sway Control and VSC systems off,
the systems will be a utomatically re-
enabled in the following situations:
●When the power switch is turned
off
●If only the TRAC sy stem is turned
off, the TRAC will turn on when
vehicle speed increases
If both the TRAC and VSC sys-
tems are turned of f, automatic re-
enabling will not occur when vehi-
cle speed increases.
■Operating conditions of Active
Cornering Assist
The system operates when the fol-
lowing occurs.
●TRAC/VSC can operate
●The driver is attempting to accel-
erate while turning
●The system detects that the vehi-
cle is drifting to the outer side
●The brake pedal is released
■Reduced effectiveness of the
EPS system
The effect iveness of the EPS sys-
tem is reduced to prevent the sys-
tem from overheating when there is
frequent steering input over an
extended period of time. The steer-
ing wheel may feel heavy as a
result. Should this occur, refrain
from excessive steering input or
stop the vehicle a nd turn the hybrid
system off. The EPS system should
return to normal within 10 minutes.
■Secondary Collision Brake
operating conditions
The system operates when the SRS
airbag sensor de tects a collision
while the vehicle is in motion. How-
ever, the system does not operate
when the components are dam-
aged.

4657-2. Steps to take in an emergency
7
When trouble arises
■High coolant temperature warning light* (warning buzzer)
*: This light illuminates on the mu lti-information display with a message.
■Hybrid system overheat warning light* (warning buzzer)
*: This light illuminates on the mu lti-information display with a message.
■Low engine oil pressure warning light* (warning buzzer)
*: This light illuminates on the mu lti-information display with a message.
■Malfunction indicator lamp
Warning lightDetails/Actions
Indicates that the engine coolant temperature is too
high
 Immediately stop the v ehicle in a safe place.
Handling method ( P.509)
Warning lightDetails/Actions
Indicates that the hybri d system has overheated
 Stop the vehicle in a safe place.
Handling method ( P.509)
Warning lightDetails/Actions
Indicates that the engine oil pressure is too low
 Immediately stop the vehicle in a safe place and
contact your Toyota dealer.
Warning lightDetails/Actions
(U.S.A.)
(Canada)
Indicates a malfunction in:
 The hybrid system;
 The electronic engi ne control system;
 The electronic throttle control system; or
 The emission control system (if equipped)
 Have the vehicle insp ected by your Toyota
dealer immediately.

4777-2. Steps to take in an emergency
7
When trouble arises
instructions (P.512).
●If any of the following messages
are shown on the multi-informa-
tion display, it may indicate a mal-
function. Have the vehicle
inspected by your Toyota dealer
immediately.
• “Smart Key System Malfunction”
• “Hybrid System Malfunction”
• “Check Engine”
• “Hybrid Battery System Malfunc-
tion”
• “Accelerator Syst em Malfunction”
●If any of the following messages
are shown on the multi-informa-
tion display, it may indicate a mal-
function. Immediately stop the
vehicle and contact your Toyota
dealer.
•“Braking Power Low”
• “12-Volt Battery Charging System Malfunction”
• “Oil Pressure Low”
●If any of the following messages
are shown on the multi-informa-
tion display, the vehicle may have
run out of fuel. Stop the vehicle in
a safe place and, if the fuel level is
low, refuel the vehicle.
• “Hybrid System Stopped”
• “Engine Stopped”
●If “Low Auxiliary Battery See
Owner’s Manual” is shown
• When the display goes off after
several seconds
*:
Maintain the hybri d system opera-
tion for more than 15 minutes and
charge the 12- volt battery.
• When the display does not go off:
Start up the hybrid system using the
procedures for “If the 12-volt battery
is discharged” ( P.504)
*: Displays for about 6 seconds
●If “Maintenance Required for Trac-
tion Battery Cooling Parts See
Owner’s Manual” is shown, the fil-
ter may be clogged, the air intake
vent may be blocked, or there may
be a gap in the duct. Therefore, perform the follo
wing correction
procedure.
• Cleaning the hybrid battery (trac-
tion battery) air intake vents
(
P.440)
If the warning message is shown
even if the vents are cleaned,
have the vehicle inspected by
your Toyota dealer.
■If “Engine Oil Level Low Add or
Replace” is displayed
The engine oil level may be low.
Check the level o f 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 message disap-
pears.
■If “Hybrid System Stopped
Steering Power Low” is dis-
played
This message is displayed if the
hybrid system is stopped while driv-
ing.
When steering wheel operations are
heavier than usual, grip the steering
wheel firmly and operate it using
more force than usual.
■If “Hybrid System Overheated
Output Power Reduced” is
shown
The message may be shown when
driving under severe operating con-
ditions. (For example, when driving
up a long steep hill or driving up a
steep hill in reverse.)
Coping method: P.512
■If “Traction Battery Needs to be
Protected Refrain from the Use
of N Position” is shown
This message may be displayed
when the shift lever is in N.
As the hybrid battery (traction bat-
tery) can not be charged when the
shift lever is in N, shift the shift lever
to P when the vehicle is stopped.

5097-2. Steps to take in an emergency
7
When trouble arises
■If the engine coolant tem-
perature gauge enters the
red zone or “Engine Cool-
ant Temp High Stop in a
Safe Place See Owner’s
Manual” is shown on the
multi-information display
1 Stop the vehicle in a safe
place and turn off the air con-
ditioning system, and then
stop the hybrid system. 2
If you see steam:
Carefully lift the hood after
the steam subsides.
If you do not see steam:
Carefully lift the hood.
3 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.
4The coolant level is satisfac-
tory if it is between the
“FULL” and “LOW” lines on
the reservoir.
Reservoir
“FULL” line
If your vehicle over-
heats
The following may indicate
that your vehicle is over-
heating.
The needle of the engine
coolant temperature gauge
( P.97, 101) enters the red
zone, or a loss of hybrid
system power is experi-
enced. (For example, the
vehicle speed does not
increase.)
 “Engine Coolant Temp High
Stop in a Safe Place See
Owner’s Manual” or “Hybrid
System Overheated Output
Power Reduced” is shown
on the multi-information dis-
play.
Steam comes out from
under the hood.
Correction procedures
A
B
A
B

574Alphabetical Index
Heated steering wheel ........... 361
HeatersFront automatic air conditioning system ................................ 348
Heated steering wheel ......... 361
Outside rear view mirrors ..... 350
Rear automatic air conditioning system ................................ 358
Seat heaters ......................... 361
High mounted stoplight Replacing light bulbs ............ 448
Hill-start assist control .......... 336
Hood ........................................ 410
Hooks Cargo hooks ......................... 372
Coat hooks ........................... 388
Grocery bag hooks ............... 387
Retaining hooks (floor mat) .... 32
Horn ......................................... 187
Hybrid battery (tr action battery)
Location.................................. 83
Specification ......................... 519
Hybrid battery (traction battery) air intake vents ............... 85, 440
Hybrid battery (traction battery) air intake vents and filters ... 440
Hybrid battery air vent ............. 85
Hybrid system .......................... 79 ACC...................................... 237
Acoustic Vehicle Alerting System............................................. 81
Emergency shut off system .... 86
Energy monitor/consumption screen ................................ 122
EV drive mode...................... 239
High voltage components....... 83
How to start the hybrid system ........................................... 234
Hybrid battery (traction battery) air vents.............................. 440
Hybrid Electric Vehicle driving tips...................................... 342 Hybrid System Indicator .97, 101
Hybrid system precautions .....83
If the hybrid sys
tem will not start
...........................................499
If your vehicle has to be stopped in an emergency .................457
Ignition switch (power switch) ...........................................234
Overheating ..........................509
Power (ignition) switch .........234
Regenerative braking .............80
Starting the hybrid system ....234
Hybrid System I ndicator .98, 102,
121
Hybrid transmissio n ...............241
S mode .................................244
I
I/M test .....................................406
Identification Engine ..................................518
Vehicle..................................517
Ignition switch (power switch) ...............................................234Auto power off fun ction.........238
Changing the power switch modes.................................237
If your vehicle has to be stopped in an emergency .................457
Starting the hybrid system ....234
Illuminated entry system .......365
Immobilizer system ..................88
Indicators ..................................94
Initialization Items to initialize ...................551
Maintenance .........................403
Oil maintenance ...................415
Tire pressure warning system...........................................427
Inside rear view m irror ...187, 189
Instrument panel light control99, 103

576Alphabetical Index
Malfunction indicator lamp.... 465
Menu icons ............................. 106
MeterClock ............................ 100, 104
Indicators................................ 94
Instrument panel light control99, 103
Meter control switches ......... 105
Meters ............................ 97, 101
Multi-information display ...... 104
Settings ........................ 112, 539
Units ............................. 115, 539
Warning lights ................ 93, 464
Warning messages .............. 475
Meter control switches .......... 105
Mirrors Digital Rear-view Mirror........ 189
Inside rear view mirror.......... 187
Outside rear view mirror defog-gers .................................... 350
Outside rear view mirrors ..... 199
Vanity mirrors ....................... 374
Moon roof Door lock linked moon roof oper-ation ................................... 205
Jam protection function ........ 205
Operation ............................. 205
Warning message ................ 206
Multi-information display Audio system-linked display . 111
Changing the display............ 105
Display contents ................... 104
Driving information display ... 106
Driving support system informa-tion display ......................... 110
Dynamic radar cruise control with full-speed range .......... 291
Energy monitor ..................... 122
Hybrid System In dicator . 98, 102
Intuitive parking assist-sensor ........................................... 312
Language ..................... 115, 539 LTA (Lane Traci
ng Assist) ....284
Menu icons ...........................106
Meter control switches..........105
PCS (Pre-Collisio n System) .270
Pop-up display......................115
Settings ........................112, 539
Suggestion function ......117, 539
Tire pressure ...... ..................424
Units .............................115, 539
Vehicle information display...111
Warning messages ...............475
N
Navigation system-linked display
...............................................118
Noise from under ve hicle...........6
Normal mode...........................334
O
Odometer...........................97, 101
Odometer and trip meter display “ODO TRIP” switch .........99, 103
“ODO TRIP” switch ..........99, 103
Oil Engine oil..............................519
Opener Back door .....................152, 154
Hood .....................................410
Open tray .................................370
Outer foot lights Replacing light bulbs ............448
Outside rear view mirrors ......199 Adjusting and folding ............199
BSM (Blind Spot M onitor) .....303
Linked mirror function when reversing.............................200
Outside rear view mirror defog- gers ....................................350
Outside temperature display .98, 102
Overheating.............................509

Alphabetical Index581
Tire inflation pressure display function............................... 424
Tire pressure warning system ........................................... 424
Uniform Tire Quality Grading 531
Warning light ........................ 470
Tools .............. .................. 481, 490
Top tether strap ... ..................... 71
Total load capacity ......... 217, 220
Towing Dinghy towing....................... 232
Towing eyelet ....................... 490
Trailer sway control .............. 336
Trailer towing................ 221, 222
Toyota Safety Sense .............. 265 AHB (Automatic High Beam) 253
Dynamic radar cruise control with full-speed range .......... 291
LTA (Lane Tracing Assist).... 278
PCS (Pre-Collision System) . 270
RSA (Road Sign Assist) ....... 288
TRAC (Traction Control) ........ 336
Traction battery (Hybrid battery) ................................................. 83Hybrid battery (traction battery) air intake vents ..................... 85
Location.................................. 83
Specification ......................... 518
Warning messages ................ 86
Traction Control (TRAC) ........ 336
Traction motor (e lectric motor)79
Trailer sway control ............... 336
Trailer towing .................. 221, 222
Transmission Driving mode select switch... 334
Hybrid transmission.............. 241
Trip meters ....... ................. 97, 101
Turn signal lights Replacing light bulbs ............ 448
Turn signal lever................... 245U
USB charging ports ................379
V
Vanity lightsVanity lights ..........................374
Wattage ................................524
Vanity mirrors .........................374
Vehicle data recordings .............7
Vehicle identification number517
Vehicle Stability Control (VSC) ...............................................336
Ventilators (seat ventilators) .361
VSC (Vehicle Stab ility Control)
...............................................336
W
Warning buzzers Approach warning ................298
Brake hold ............................469
Brake Override System ........469
Brake system ........................464
Downshifting .........................244
Drive-Start Control ................469
Electric power steering .........466
High coolant temperature .....465
Hybrid system overheat ........465
Intuitive parking assist OFF indi- cator ...................................467
Intuitive parking assist ..........312
Low engine oil pressure .......465
LTA (Lane Traci ng Assist) ....278
LTA indicator ........................467
Open door ............................136
Open hood............................136
Open window........................203
PKSB OFF indicator .............468
Pre-collision warn ing ............270
RCD OFF indicator ...............468
RCTA (Rear Cross Traffic Alert)

582Alphabetical Index
........................................... 303
RCTA OFF indicator............. 468
Seat belt reminder ................ 471
Vehicle sway warning........... 282
Warning lights ABS ...................................... 466
Brake hold operated indicator........................................... 469
Brake Override System ........ 469
Brake system ....................... 464
Charging system .................. 464
Drive-Start Control ............... 469
Electric power steering ......... 466
Engine .................................. 465
High coolant temperature ..... 465
Hybrid system overheat ....... 465
Intuitive parking assist OFF indi- cator ................................... 467
Low engine oil pressure ....... 465
Low fuel level ....................... 470
LTA indicator ........................ 467
Malfunction indicator lamp ... 465
Parking brake indicator ........ 470
PCS warning light................. 467
PKSB (Parking Support Brake) ........................................... 469
PKSB OFF indicato r ............. 468
RCD OFF indicator............... 468
RCTA OFF indicator............. 468
Seat belt reminder light ........ 471
Slip indicator......................... 469
SRS ...................................... 466
Tire pressure ........................ 470
Warning messages ................ 475
Washer Checking .............................. 418
Low washer fluid warning mes-sage ........................... 418, 475
Preparing and c hecking before
winter.................................. 344
Switch........................... 257, 260
Washing and waxing .............. 396 Weights
Cargo capacity .............217, 220
Load limits ............................220
Wheels .....................................437 Replacing wheels .................437
Size ......................................523
Window glasses Power windows ....................202
Window lock switch ...............204
Windows Power windows ....................202
Rear window defogger .........350
Washer .........................257, 260
Windshield defogge r ..............349
Windshield wiper d e-icer .......353
Windshield wipers Intermittent windshield wipers...........................................257
Position.........................257, 260
Rain-sensing windshield wipers ...........................................257
Winter driving tips ..................344
Wireless charger.....................381
Wireless remote control.........130 Battery-saving function .........166
Locking/Unlocking ................130
Panic mode ..........................130
Replacing the battery ...........444
For vehicles with Entune Audio, Entune Audio Plus
or Entune Premium Audio,
refer to the “NAVIGA-
TION AND MULTIMEDIA
SYSTEM OWNER’S MAN-
UAL” for information
regarding the equipment
listed below.
· Navigation system