Page 222 of 664
222
SIENNA_OM_01999-08001_(U)
4-1. Before driving
Dinghy towing
Your vehicle is not designed to be dinghy towed (with 4 wheels
on the ground) behind a motor home.
NOTICE
■To avoid serious damage to your vehicle
■ To prevent causing serious damage to the transaxle and Active Torque
Control 4WD system (AWD models)
Do not tow your vehicle with four wheels
on the ground.
ITN25N009
2WD models: Never tow this vehicle from
the rear with the front wheels on the
ground. This may cause serious damage
to the transaxle.
AWD models: Never tow this vehicle with
any of the wheels on the ground. This
may cause serious damage to the tran-
saxle and Active Torque Control 4WD
system.
ITN25N010
ITN25N011
Page 291 of 664

291
SIENNA_OM_01999-08001_(U)
4-5. Using the driving support systems
4
Driving
Driving assist systems
◆ABS (Anti-lock Brake System)
Helps to prevent wheel lock when the brakes are applied suddenly,
or if the brakes are applied while driving on a slippery road surface
◆Brake assist
Generates an increased level of braking force after the brake pedal
is depressed when the system detects a panic stop situation
◆VSC (Vehicle Stability Control)
Helps the driver to control skidding when swerving suddenly or
turning on slippery road surfaces
◆TRAC (Traction Control)
Helps to maintain drive power and prevent the drive wheels from
spinning when starting the vehicle or accelerating on slippery roads
◆Hill-start assist control (if equipped)
Helps to prevent the vehicle from rolling backward when starting on
an incline or slippery slope
◆EPS (Electric Power Steering)
Employs an electric motor to redu ce the amount of effort needed to
turn the steering wheel
◆Active Torque Control 4WD (AWD models only)
Automatically switches from front-wheel drive to AWD (All-Wheel
Drive) according to driving condit ions, helping to ensure reliable
handling and stability. Examples of conditions where the system will
switch to AWD are when cornering, going uphill, starting off or
accelerating, and when the road surface is slippery due to snow or
rain etc.
To help enhance driving safety and performance, the following
systems operate automatically in response to various driving
situations. Be aware, however, that these systems are supple-
mentary and should not be relied upon too heavily when operat-
ing the vehicle.
Page 295 of 664

SIENNA_OM_01999-08001_(U)
2954-5. Using the driving support systems
4
Driving
WARNING
■TRAC may not operat e effectively when
Directional control and power may not be achievable while driving on slip-
pery road surfaces, even if the TRAC system is operating.
Drive the vehicle carefully in conditions where stability and power may be
lost.
■ Hill-start assist control (vehicles with a hill-start assist control system)
● Do not overly rely on hill-start assist control. Hill-start assist control may
not operate effectively on steep inclines and roads covered with ice.
● Unlike the parking brake, hill-start assist control is not intended to hold the
vehicle stationary for an extended period of time. Do not attempt to use
hill-start assist control to hold the vehicle on an incline, as doing so may
lead to an accident.
■ When the VSC is activated
The slip indicator light flashes. Always drive carefully. Reckless driving may
cause an accident. Exercise particular care when the indicator light flashes.
■ When the TRAC/VSC syst ems are turned off
Be especially careful and drive at a speed appropriate to the road condi-
tions. As these are the systems to help ensure vehicle stability and driving
force, do not turn the TRAC/VSC systems off unless necessary.
■
Replacing tires
Make sure that all tires are of the specified size, brand, tread pattern
and total load capacity. In addition, make sure that the tires are inflated
to the recommended tire inflation pressure level.
The ABS, TRAC and VSC systems will not function correctly if different
tires are installed on the vehicle.
Contact your Toyota dealer for further information when replacing tires
or wheels.
■Handling of tires and suspension
Using tires with any kind of problem or modifying the suspension will
affect the driving assist systems, and may cause the system to malfunc-
tion.
■ Active Torque Control 4WD system (AWD models only)
● The AWD system of this vehicle is intended to ensure driving stability on
normal roads. It is not designed for use in demanding situations such as
rally driving.
● Take care when driving on slippery road surfaces.
Page 534 of 664
5348-2. Steps to take in an emergency
SIENNA_OM_01999-08001_(U)
NOTICE
■To prevent damaging the vehicle when towing using a wheel-lift type
truck
When raising the vehicle, ensure adequate ground clearance for towing at
the opposite end of the raised vehicle. Without adequate clearance, the
vehicle could be damaged while being towed.
■ To prevent body damage when towing with a sling-type truck
Do not tow with a sling-type truck, either from the front or rear.
■ Recreational towing (beh ind motor home, etc.)
Never dinghy tow your vehicle to prevent
causing serious damage to the Active
Torque Control 4WD system (AWD mod-
els) and transaxle. (P. 222)
Page 553 of 664
5538-2. Steps to take in an emergency
SIENNA_OM_01999-08001_(U)
8
When trouble arises
Indicates abnormal engine oil pressureA buzzer also sounds.
Immediately stop the vehicle in a safe place
and contact your Toyota dealer.
(AWD models)
Indicates a malfunction in the Active Torque
Control 4WD system
A buzzer also sounds.
Have the vehicle inspected by your Toyota
dealer.
Vehicles without a smart key system:
Indicates that the engine switch is turned to the
“LOCK” position, the key is removed and the
driver’s door is opened while the lights are turned
on.
Vehicles with a smart key system:
Indicates that the engine switch is turned off and
the driver’s door is opened while the lights are
turned on. A buzzer also sounds.
Turn the lights off.
Warning messageDetails/Actions
(Flashes)
Page 554 of 664
5548-2. Steps to take in an emergency
SIENNA_OM_01999-08001_(U)
(AWD models)
Indicates the Active Torque Control 4WD system
has overheatedA buzzer also sounds.
Immediately stop the vehicle in a safe place
and contact your Toyota dealer.
Indicates a malfunction in the brake override sys-
tem A buzzer also sounds.
Have the vehicle inspected by your Toyota
dealer.
(If equipped)
Indicates a malfunction in the Automatic High
Beam system
A buzzer also sounds.
Have the vehicle inspected by your Toyota
dealer.
Warning messageDetails/Actions
(Flashes)
Page 649 of 664

649Alphabetical index
SIENNA_OM_01999-08001_(U)
Alphabetical index
A/C .................................... 404, 413Air conditioning filter ............. 501
Front automatic air
conditioning system ............ 404
Rear automatic air
conditioning system ............ 413
ABS (Anti-lock Brake System) .................................. 291
Function ................................ 291
Warning light ......................... 538
Warning message ................. 549
Active head restraint ............... 149
Active Torque Control 4WD system ........................... 291
Function ................................ 291
Warning message ......... 553, 554
Air conditioning filter .............. 501
Air conditioning system
Air conditioning filter ............. 501
Front automatic air conditioning system ............ 404
Rear automatic air conditioning system ............ 413 Airbags ....................................... 36
Airbag operating
conditions ............................. 45
Airbag precautions for your child......................... 39
Airbag warning light .............. 538
Correct driving posture ........... 26
Curtain shield airbag operating conditions ............. 46
Curtain shield airbag precautions........................... 39
Front passenger occupant classification syst em ............ 50
General airbag
precautions........................... 39
Locations of airbags ............... 36
Modification and disposal of airbags ............... 44
Side and curtain shield airbags operating
conditions ............................. 46
Side and curtain shield airbags precautions .............. 39
SRS airbag instructions for Canadian owners .......... 633
SRS airbags ........................... 36
A