2012 TOYOTA SIENNA engine

319
2-4. Using other
driving systems
2
When driving
SIENNA_U (OM45477U)
■Sensor detection information
● Certain vehicle conditions and the surrounding environment may affect
the ability of the sensor to correctly detect obstacles. Particular instances
where this may occur are listed below.
• There is dirt, snow or ice on the sensor.
• The sensor is frozen.
• The sensor is covered in any way.
• The vehicle is leaning considerably to one side.
• On an extremely bumpy road, on an incline, on gravel, or on grass
• The vicinity of the vehicle is noisy due to vehicle horns, motorcycle
engines, air brakes of large vehicles, or other loud noises producing
ultrasonic waves.
• There is another vehicle equipped with parking assist sensors in the vicinity.
• A sensor is coated with a sheet of spray or heavy rain.
• The vehicle is equipped with a fender pole or radio antenna.
• A bumper or sensor receives a strong impact.
• The vehicle is approaching a tall or right-angled curb.
• In harsh sunlight or intense cold weather
In addition to the examples above, there are instances in which, because of
their shapes, signs and other objects may be judged by the sensor to be
closer than they are.
● The shape of the obstacle may prevent the sensor from detecting it. Pay
particular attention to the following obstacles:
• Wires, fences, ropes etc.
• Cotton, snow and other materials that absorb sound waves
• Sharply-angled objects
• Low obstacles
• Tall obstacles with upper sections projecting outwards in the direction
of your vehicle

328 2-4. Using other driving systems
SIENNA_U (OM45477U)
When the Enhanced VSC/TRAC systems are operatingIf the vehicle is in danger of slip-
ping or if any of the drive wheels
spins, the slip indicator light
flashes to indicate that the
Enhanced VSC/TRAC systems
are operating.
A buzzer (intermittent) sounds to
indicate that VSC is operating.
■Active Torque Control 4WD (AWD models only)
Automatically switches from front-wheel drive to AWD (All-Wheel Drive)
according to driving conditions, helping to ensure reliable handling and
stability. Examples of conditions where the system will switch to AWD
are when cornering, going uphill, star ting off or accelerating, and when
the road surface is slippery due to snow or rain etc.
■ VDIM (Vehicle Dynamics In tegrated Management) (if
equipped)
Provides integrated control of the ABS, brake assist, TRAC, VSC, hill-
start assist control, and EPS systems
Helps to maintain vehicle stability when swerving on slippery road sur-
faces by controlling the brakes and engine output
■ PCS (Pre-Collision System) (if equipped)
P. 336

329
2-4. Using other
driving systems
2
When driving
SIENNA_U (OM45477U)
Disabling TRAC and VSC system
If the vehicle gets stuck in fresh snow or mud, TRAC and VSC may
reduce power from the engine to the wheels. You may need to turn
the system off to enable you to rock the vehicle in order to free it.
■ Turning off the TRAC system only
To turn the TRAC system off,
quickly press and release the
button.
The “TRAC OFF” indicator light
will come on.
Push the button again to turn the
system back on.
■Turning off both TRAC and VSC systems
To turn the TRAC and VSC sys-
tems off, press and hold the but-
ton for more than 3 seconds
while the vehicle is stopped.
The “TRAC OFF” indicator light
and VSC OFF indicator light will
come on.
Press the button again to turn the
systems back on.

330 2-4. Using other driving systems
SIENNA_U (OM45477U)
■When the “TRAC OFF” indicator light comes on even if the VSC OFF
switch has not been pressed
TRAC and hill-start assist control cannot be operated. Contact your Toyota
dealer.
■ Sounds and vibrations caused by ABS, brake assist, Enhanced VSC
and TRAC
● A sound may be heard from the engine compartment when the engine is
started or just after the vehicle begins to move. This sound does not indi-
cate that a malfunction has occurred in any of these systems.
● Any of the following conditions may occur when the above systems 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 after the vehicle comes to a stop.
• The brake pedal may pulsate slightly after ABS is activated.
• The brake pedal may move down slightly after ABS is activated.
■ EPS operation sound
When the steering wheel is operated, a motor sound (whirring sound) may
be heard. This does not indicate a malfunction.
■ Reactivation of the TRAC and VSC systems after turning off the engine
Turning off the engine after turning off the TRAC and VSC systems will auto-
matically reactivate them.
■ Reactivation of the TRAC system linked to vehicle speed
When only the TRAC system is turned off, the TRAC system will turn on
when vehicle speed increases. However, when both TRAC and VSC sys-
tems are turned off, the systems will not turn on even when vehicle speed
increases.

331
2-4. Using other
driving systems
2
When driving
SIENNA_U (OM45477U)
■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 engine
off. The EPS system should return to normal within 10 minutes.
CAUTION
■ABS does not operate effectively when
● Tires with inadequate gripping ability are used (such as excessively worn
tires on a snow covered road).
● The vehicle hydroplanes while driving at high speed on wet or slick roads.
■ Stopping distance when ABS is oper ating may exceed that of normal
conditions
The ABS is not designed to shorten the vehicle’s stopping distance. Always
maintain a safe distance from the vehicle in front of you in the following situ-
ations.
● When driving on dirt, gravel or snow-covered roads
● When driving with tire chains
● When driving over bumps in the road
● When driving over roads with potholes or roads with uneven surfaces
■ TRAC may not operate effectively when
Directional control and power may not be achievable while driving on slip-
pery road surfaces, even if the TRAC system is operating.
Do not drive the vehicle in conditions where stability and power may be lost.

352
2-5. Driving information
SIENNA_U (OM45477U)
Winter driving tips
Carry out the necessary preparations and inspections before driving
the vehicle in winter. Always drive the vehicle in a manner appropri-
ate to the prevailing weather conditions.
■ Pre-winter preparations
●Use fluids that are appropriate to the prevailing outside tem-
peratures.
• Engine oil
• Engine coolant
• Washer fluid
● Have a service technician inspect the level and specific grav-
ity of battery electrolyte.
● Have the vehicle fitted with four snow tires or purchase a set
of tire chains for the front tires.
Ensure that all tires are the same size and brand, and that chains
match the size of the tires.
■Before driving the vehicle
Perform the following according to the driving conditions:
●Do not try to forcibly open a window or move a wiper that is
frozen. Pour warm water over the frozen area to melt the ice.
Wipe away the water immediately to prevent it from freezing.
● To ensure proper operation of th e climate control system fan,
remove any snow that has accumulated on the air inlet vents
in front of the windshield.
● Remove any ice that has accumu lated on the vehicle chassis.
● Periodically check for and remove any excess ice or snow
that may have accumulated in the wheel well or on the
brakes.

368 2-5. Driving information
SIENNA_U (OM45477U)●
Take care when passing other v ehicles. Passing requires consider-
able distance. After passing a vehi cle, do not forget the length of
your trailer, and be sure you hav e plenty of room before changing
lanes.
● To maintain engine braking efficiency and charging system perfor-
mance when using engine braking, do not put the transmission in
D.
Transmission shift range position must be in 4 in the S mode.
● Instability happens more frequently when descending steep or long
downhill grades. Before descending, slow down and downshift. Do
not make sudden downshifts while descending steep or long down-
hill grades.
● Avoid holding the brake pedal down too long or applying the
brakes too frequently. This could cause the brakes to overheat and
result in reduced braking efficiency.
● Due to the added load of the trailer, your vehicle’s engine may
overheat on hot days (at temper atures over 85°F [30°C]) when
driving up a long or steep grade. If the Engine coolant temperature
gauge overheating, immediately turn off the air conditioning (if in
use), pull your vehicle off the road and stop in a safe spot.
(  P. 775)

369
2-5. Driving information
2
When driving
SIENNA_U (OM45477U)
●
Always place wheel blocks under both the vehicle’s and the
trailer’s wheels when parking. Ap ply the parking brake firmly, and
put the transmission in P. Avoid pa rking on a slope, but if unavoid-
able, do so only after performing the following:
Apply the brakes and keep them applied.
Have someone place wheel blo cks under both the vehicle’s
and trailer’s wheels.
When the wheel blocks are in pl ace, release the brakes slowly
until the blocks absorb the load.
Apply the parking brake firmly.
Shift into P and turn off the engine.
● When restarting after parking on a slope:
With the transmission in P, start the engine. Be sure to keep
the brake pedal pressed.
Shift into a forward gear. If reversing, shift into R.
Release the parking brake and brake pedal, and slowly pull or
back away from the wheel blocks. Stop and apply the brakes.
Have someone retrieve the blocks.
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