engine TOYOTA SIENNA HYBRID 2021 (in English) Repair Manual

4677-2. 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.511)
Warning lightDetails/Actions
Indicates that the hybri d system has overheated
 Stop the vehicle in a safe place.
Handling method ( P.511)
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.

4787-2. Steps to take in an emergency
*: A buzzer sounds the first time a message is show n on the multi-informa-
tion display.
■Warning messages
The warning messages explained
below may differ from the actual
messages according to operation
conditions and vehicle specifica-
tions.
■Warning buzzer
In some cases, the buzzer may not
be heard due to being in a noisy
location or audio sound.
■If a message that indicates the
need for visiting your Toyota
dealer is displayed
The system or part shown on the
multi-information di splay is malfunc-
tioning. Have the vehicle inspected
by your Toyota dealer immediately.
■If a message that indicates the
need for referring to Owner’s
Manual is displayed
●If “Engine Coolant Temp High
Stop in a Safe Place See Owner’s
Manual” is shown, follow the
instructions ( P.514).
●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 System Malfunction”
●If any of the following messages
are shown on the multi-informa-
Warning lightWarning buzzer*Warning
Sounds
• Indicates an import ant situation, such
as when a system related to driving is
malfunctioning or that danger may
result if the correction procedure is not
performed
• Indicates a situat ion, such as when
damage to the vehicle or danger may
result
Comes on or flashesSounds
Indicates an importan t situation, such as
when the systems shown on the multi-
information display may be malfunction-
ing
Does not sound
• Indicates a condition, such as malfunc- tion of electrical components, their con-
dition, or indicat es the need for
maintenance
• Indicates a situatio n, such as when an
operation has been performed incor-
rectly, or indicates how to perform an
operation correctly

4797-2. Steps to take in an emergency
7
When trouble arises
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.506)
*: 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 following correction
procedure.
• If the air intake vent or filter of the hybrid battery (traction battery)
are dirty, perform the procedures
on P.443to clean them.
• If the warning message is shown when the air intake vent and filter
of the hybrid battery (traction bat-
tery) are not dirty, have the vehicle
inspected at your Toyota dealer.
■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 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.514
■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.
■If “Traction Battery Needs to be
Protected Shift into P to
Restart” is shown
This message is displayed when the
hybrid battery (traction battery)
charge has becom e extremely low
because the shift lever has been left
in N for a certain amount of time.
When operating the vehicle, shift to
P and restart the hybrid system.
■If “Shift to P Before Exiting
Vehicle” is shown
Message is displayed when the
driver’s door is opened without turn-

4807-2. Steps to take in an emergency
ing the power switch to OFF with the
shift lever in any position other than
P.
Shift the shift lever to P.
■If “Shift Is in N Release Acceler-
ator Before Shifting” is shown
Message is displayed when the
accelerator pedal has been
depressed and the shift lever is in N.
Release the accelerator pedal and
shift the shift lever to D or R.
■If “Accelerator Pedal is
Pressed” is displayed
The accelerator pedal has been
depressed when the shift lever is in
P. Release the accelerator pedal.
■If “Press Brake When Vehicle Is
Stopped Hybrid System May
Overheat” is shown
Message is displayed when the
accelerator pedal is depressed to
maintain the vehicle position when
stopped on a upward slope, etc.
If this continues, the hybrid system
may overheat.
Release the accelerator pedal and
depress the brake pedal.
■If “Auto Power Off to Conserve
Battery” is shown
Power was turned off due to the
automatic power off function.
Next time when starting the hybrid
system, operate th e hybrid system
for approximatel y 5 minutes to
recharge the 12-volt battery.
■If “High Power Consumption
Power to Climate Temporarily
Limited” is displayed
Turn off unnecessary electronic
equipment to reduce power con-
sumption.
Please wait until th e power supply
returns to normal.
■If “Headlight System Malfunc-
tion Visit Your D ealer” is dis-
played
The following systems may be mal- functioning.
Have the vehicle inspected by your
Toyota dealer immediately.
●The LED headlight system
●Automatic High Beam
■If “Radar Cruise Control
Unavailable” is shown
The dynamic radar cruise control
with full-speed range system is sus-
pended temporarily or until the prob-
lem shown in the message is
resolved. (causes and coping meth-
ods: P.265)
■If a message that indicates the
malfunction of front camera is
displayed
The following systems may be sus-
pended until the problem shown in
the message is resolved. (P.265,
466)
●PCS (Pre-Collision System)
●LTA (Lane Tracing Assist)
●Automatic High Beam
●RSA (Road Sign Assist) (if
equipped)
●Dynamic radar cruise control with
full-speed range
■If “Oil Maintenance Required
Soon” is displayed
Indicates that the engine oil should
be scheduled to be changed.
Check the engine oil and change it if
necessary.
After changing the engine oil, make
sure to reset t he message.
(  P.418)
■If “Oil Maintenance Required
Visit Your Deale r” is displayed
Indicates that the engine oil should
be changed.
Check and change the engine oil
and oil filter by yo ur Toyota dealer.
After changing the engine oil, make
sure to reset t he message.
(  P.418)

4987-2. Steps to take in an emergency
76 ft•lbf (103 N•m, 10.5 kgf•m)
5Stow the flat tire, tire jack and
all tools.
■The compact spare tire
●The compact spare tire is identi-
fied by the label “TEMPORARY
USE ONLY” on the tire sidewall.
Use the compact s pare tire tem-
porarily, and only in an emer-
gency.
●Make sure to check the tire infla-
tion pressure of the compact
spare tire. ( P.525)
■When using the compact spare
tire
As the compact sp are tire is not
equipped with a tire pressure warn-
ing valve and transmitter, low infla-
tion pressure of the spar e tire will
not be indicated by the tire pressure
warning system. Also, if you replace
the compact spare tire after the tire
pressure warning light comes on,
the light remains on.
■When the compact spare tire is
attached
The vehicle height may become
lower when driving with the compact
spare tire compared to when driving
with standard tires.
■If you have a flat front tire on a
road covered with snow or ice
Install the compact spare tire on one
of the rear wheels of the vehicle.
Perform the following steps and fit
tire chains to the front tires: 1
Replace a rear tire with the com-
pact spare tire.
2 Replace the flat front tire with the
tire removed from the rear of the
vehicle.
3 Fit tire chains to the front tires.
WARNING
■When using the compact
spare tire
●Remember that the compact
spare tire provided is specifi-
cally designed for use with your
vehicle. Do not use your com-
pact spare tire on another vehi-
cle.
●Do not use more than one com-
pact spare tire simultaneously.
●Replace the comp act spare tire
with a standard tire as soon as
possible.
●Avoid sudden acceleration,
abrupt steering, sudden brak-
ing and shifting operations that
cause sudden engine braking.
■When the compact spare tire
is attached
The vehicle speed may not be
correctly detected, and the follow-
ing systems may not operate cor-
rectly:
• ABS & Brake assist
• VSC/Trailer Sway Control
• TRAC
• Dynamic radar cruise control with full-speed range
• PCS (Pre-Collision System)
• EPS
• LTA (Lane Tracing Assist)
• Tire pressure warning system
• AHB (Automatic High Beam)

5077-2. Steps to take in an emergency
7
When trouble arises
on the second vehicle and connect the clamp at the other end of
the negative cable to .
Exclusive jump starting terminal (your vehicle)
Positive (+) battery terminal (second vehicle)
Negative (-) battery term inal (second vehicle)
Solid, stationary, unpainted metallic point away from the exclu -
sive jump starting terminal and any moving parts as shown in th e
illustration
5 Start the engine of the sec-
ond vehicle. Increase the
engine speed slightly and
maintain at that level for
approximately 5 minutes to
recharge the 12-volt battery
of your vehicle.
6 Open and close any of the
doors of your vehicle with the
power switch OFF.
7 Maintain the engine speed of
the second vehicle and start
the hybrid system of your
vehicle by turning the power
switch to ON. 8
Make sure the “READY” indi-
cator comes on. If the indica-
tor light does not come on,
contact your Toyota dealer.
9 Once the hybrid system has
started, remove the jumper
cables in the exact reverse
order from which they were
connected.
10Close the exclusive jump starting terminal cover, and
reinstall the fuse box cover to
its original position.
Once the hybrid system starts,
have the vehicle inspected at
your Toyota dealer as soon as
D
A
B
C
D

5117-2. 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

5127-2. Steps to take in an emergency
“LOW” line
5 Add coolant if necessary.
Water can be us ed in an emer-
gency if engine coolant is unavail-
able.
6 Start the hybrid system and
turn the air conditioning sys-
tem on to check that the radi-
ator cooling fan operates and
to check for coolant leaks
from the radiator or hoses.
The fan operates when the air con-
ditioning system is turned on imme-
diately after a cold start. Confirm
that the fan is op erating by check-
ing the fan sound and air flow. If it is
difficult to check th ese, turn the air
conditioning system on and off
repeatedly. (The f an may not oper-
ate in freezing temperatures.)
7 If the fan is not operating:
Stop the hybrid system
immediately and contact your
Toyota dealer.
If the fan is operating:
Have the vehicle inspected at
the nearest Toyota dealer.
8 Check if “Engine Coolant
Temp High Stop in a Safe
Place See Owner’s Manual”
is shown on the multi-infor-
mation display.
If the message does not disappear:
Stop the hybrid system and contact
your Toyota dealer.
If the message is not displayed:
Have the vehicle inspected at the
nearest Toyota dealer.
■If “Hybrid System Over-
heated Output Power
Reduced” is shown on the
multi-information display
1 Stop the vehicle in a safe
place.
2 Stop the hybrid system and
carefully lift the hood.
3 After the hybrid system has
cooled down, inspect the
hoses and radiator core (radi-
ator) 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
C
A
B

5137-2. Steps to take in an emergency
7
When trouble arises
“FULL” and “LOW” lines on
the reservoir.
Reservoir
“FULL” line
“LOW” line
5 Add coolant if necessary.
Water can be used in an emer-
gency if power control unit coolant
is unavailable.
6After stopping the hybrid sys-
tem and waiting for 5 minutes
or more, start the hybrid sys-
tem again and check for 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 Toyota dealer.
A
B
C
WARNING
■When inspecting under the
hood of your vehicle
Observe the following precau-
tions.
Failure to do so may result in seri-
ous injury such as burns.
●If steam is seen coming from
under the hood, do not open the
hood until the steam has sub-
sided. The engine compart-
ment may be very hot.
●After the hybrid system has
been turned off , check that the
“READY” indicator is off.
When the hybrid system is oper-
ating, the gasoline engine may
automatically start, or the cool-
ing fan 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 reser-
voir cap while the hybrid system
and radiator are hot.
High temperature steam or
coolant could spray out.
NOTICE
■When adding engine/power
control unit coolant
Add coolant slowly after the
hybrid system has cooled down
sufficiently. Adding cool coolant to
a hot hybrid system too quickly
can cause damage to the hybrid
system.

5208-1. Specifications
■Engine number
The engine number is stamped on the engine block as shown.
Front
Engine
Model2.5 L 4-cylinder (A25A-FXS)
Type4-cylinder in line
, 4-cycle, gasoline
Bore and stroke3.44  4.07 in. (87.5  103.4 mm)
Displacement151.8 cu. in. (2487 cm3)
Valve clearanceAutomatic adjustment
Fuel
Fuel typeUnleaded gasoline only
Octane Rating87 (Research Octane Number 91) or
higher
Fuel tank capacity (Reference)18 gal. (68.2 L, 15 Imp.gal.)
Electric motor (traction motor)
TypePermanent magnet synchronous motor
Maximum output134 kW
Maximum torque199 ft•lbf (270 N•m, 27.5 kgf•m)