1998 TOYOTA SIENNA Owners Manual

name. SIENNA (U)
169
NOTICE
Do not use gasohol other than
stated above. It will cause fuel sys-
tem damage or vehicle performance
problems.
If driveability problems occur (poor
hot starting, vaporizing, engine
knock, etc.), discontinue the use.
Take care not to spill gasohol dur-
ing refueling. Gashol may cause
paint damage.
FUEL TANK CAPACITY
79 L (21 gal., 17.5 lmp. gal.)
Operation in foreign countries
If you plan to drive your Toyota in
another country...
First, comply with the vehicle registration
laws.
Second, confirm the availability of the cor-
rect fuel (unleaded and minimum octane
number).
Three−way catalytic converter
The three−way catalytic converter is an
emission control device installed in the
exhaust system.
The purpose is to reduce pollutants in the
exhaust gas.
CAUTION
Keep people and combustible mate-
rials away from the exhaust pipe
while the engine is running. The
exhaust gas is very hot.
Do not drive, idle or park your ve-
hicle over anything that might burn
easily such as grass, leaves, paper
or rags.
ProCarManuals.com

name. SIENNA (U)
170
NOTICE
A large amount of unburned gases
flowing into the three−way catalytic
converter may cause it to overheat
and create a fire hazard. To prevent
this and other damage, observe the
following precautions:
Use only unleaded gasoline.
Do not drive with an extremely low
fuel level; running out of fuel could
cause the engine to misfire, creat-
ing an excessive load on the three−
way catalytic converter.
Do not allow the engine to run at
idle speed for more than 20 min-
utes.
Avoid racing the engine.
Do not push−start or pull−start your
vehicle.
Do not turn off the ignition while
the vehicle is moving.
Keep your engine in good running
order. Malfunctions in the engine
electrical system, electronic ignition
system/distributor ignition system
or fuel system could cause an ex-
tremely high three−way catalytic
converter temperature.
If the engine becomes difficult to
start or stalls frequently, take your
vehicle in for a check−up as soon
as possible. Remember, your Toyota
dealer knows your vehicle and its
three−way catalytic converter sys-
tem best.
To ensure that the three−way cata-
lytic converter and the entire emis-
sion control system operate proper-
ly, your vehicle must receive the
periodic inspections required by the
Toyota Maintenance Schedule. For
scheduled maintenance information,
refer to the separate ”Owner’s
Manual Supplement/Maintenance
Schedule”.
Engine exhaust cautions
CAUTION
Avoid inhaling the engine exhaust.
It contains carbon monoxide, which
is a colorless and odorless gas. It
can cause unconsciousness or even
death.
Make sure the exhaust system has
no holes or loose connections. The
system should be checked from
time to time. If you hit something,
or notice a change in the sound of
the exhaust, have the system
checked immediately.
Do not run the engine in a garage
or enclosed area except for the
time needed to drive the vehicle in
or out. The exhaust gases cannot
escape, making this a particularly
dangerous situation.
Do not remain for a long time in a
parked vehicle with the engine run-
ning. If it is unavoidable, however,
do so only in an unconfined area
and adjust the heating or cooling
system to force outside air into the
vehicle.
ProCarManuals.com

name. SIENNA (U)
171 
Keep the back door and quarter
windows closed while driving. An
open or unsealed back door and
quarter windows may cause exhaust
gases to be drawn into the vehicle.
To allow proper operation of your
vehicle’s ventilation system, keep
the inlet grilles in front of the wind-
shield clear of snow, leaves, or oth-
er obstructions.
If you smell exhaust fumes in the
vehicle, drive with the windows
open and the back door and quarter
windows closed. Have the cause im-
mediately located and corrected.
FUNCTIONS OF ENGINE OIL
Engine oil has the primary functions of
lubricating and cooling the inside of the
engine, and plays a major role in main-
taining the engine in proper working order.
ENGINE OIL CONSUMPTION
It is normal that an engine should con-
sume some engine oil during normal
engine operation. The causes of oil
consumption in a normal engine are as
follows.
Oil is used to lubricate pistons, piston
rings and cylinders. A thin film of oil
is left on the cylinder wall when a pis-
ton moves downwards in the cylinder.
High negative pressure generated when
the vehicle is decelerating sucks some
of this oil into the combustion chamber.
This oil as well as some part of the oil
film left on the cylinder wall is burned
by the high temperature combustion
gases during the combustion process.
Oil is also used to lubricate the stems
of the intake valves. Some of this oil
is sucked into the combustion chamber
together with the intake air and is
burned along with the fuel. High tem-
perature exhaust gases also burn the
oil used to lubricate the exhaust valve
stems.The amount of engine oil consumed de-
pends on the viscosity of the oil, the
quality of the oil and the conditions the
vehicle is driven under.
More oil is consumed by high−speed driv-
ing and frequent acceleration and decel-
eration.
A new engine consumes more oil, since
its pistons, piston rings and cylinder walls
have not become conditioned.
When judging the amount of oil con-
sumption, note that the oil may become
diluted and make it difficult to judge
the true level accurately.
As an example, if a vehicle is used for
repeated short trips, and consumes a nor-
mal amount of oil, the dipstick may not
show any drop in the oil level at all, even
after 1000 km (600 miles) or more. This
is because the oil is gradually becoming
diluted with fuel or moisture, making it
appear that the oil level has not changed.
The diluting ingredients evaporate out
when the vehicle is then driven at high
speeds, as on an express way, making it
appear that oil is excessively consumed
after driving at high speeds.
Facts about engine oil
consumption
ProCarManuals.com

name. SIENNA (U)
172
IMPORTANCE OF ENGINE OIL LEVEL
CHECK
One of the most important points in prop-
er vehicle maintenance is to keep the en-
gine oil at the optimum level so that oil
function will not be impaired. Therefore, it
is essential that the oil level be checked
regularly. Toyota recommends that the oil
level be checked every time you refuel
the vehicle.
NOTICE
Failure to check the oil level regularly
could lead to serious engine trouble
due to insufficient oil.
For detailed information on oil level check,
see ”Checking the engine oil level” in
Chapter 7−2.
Your engine is fitted with twin ground
electrode platinum−tipped spark plugs.
NOTICE
Use only twin ground electrode plati-
num−tipped spark plugs for your en-
gine performance.
Brake system
TANDEM MASTER CYLINDER BRAKE
SYSTEM
The tandem master cylinder brake system
is a hydraulic system with two separate
sub−systems. If either sub−system should
fail, the other will still work. However, the
pedal will be harder to press, and your
stopping distance will be longer. Also, the
brake system warning light may come on.
CAUTION
Do not drive your vehicle with only a
single brake system. Have your
brakes fixed immediately.
BRAKE BOOSTER
The brake booster uses engine vacuum to
power−assist the brakes. If the engine
should quit while you are driving, you can
bring the vehicle to a stop with normal
pedal pressure. There is enough reserve
vacuum for one or two stops—but no
more!
Twin ground electrode
platinum−tipped spark plugs
ProCarManuals.com

name. SIENNA (U)
173
CAUTION
Do not pump the brake pedal if the
engine stalls. Each push on the
pedal uses up your vacuum reserve.
Even if the power assist is com-
pletely lost, the brakes will still
work. But you will have to push the
pedal hard—much harder than nor-
mal. And your braking distance will
be longer.
ANTI−LOCK BRAKE SYSTEM (with
”ABS” warning light)
The anti−lock brake system is designed to
automatically help prevent lock−up of the
wheels during sudden braking or braking
on slippery road surfaces. This assists in
providing directional stability and steering
performance of the vehicle under these
circumstances.
The anti−lock brake system becomes op-
erative after the vehicle has accelerated
to a speed in excess of approximately 10
km/h (6 mph). It stops operating when the
vehicle decelerate to a speed below
approximately 5 km/h (3 mph).You may hear a sound and feel a vibra-
tion in the engine compartment for a few
seconds when the engine is started or just
after the vehicle is started. This means
that the anti−lock brake system is in the
self check mode, and does not indicate a
malfunction.
Effective way to press the ”ABS” brake
pedal: When the anti−lock brake system
function is in action, you may feel the
brake pedal pulsating and hear a noise.
In this situation, to let the anti−lock
brake system work for you, just hold the
brake pedal down more firmly. Do not
pump the brake. This will result in re-
duced braking performance.
The brake pedal pulsation caused by the
anti−lock brake system may indicate haz-
ardous road surface conditions. Although
the anti−lock brake system assists in pro-
viding vehicle control, it is still important
to drive with all due care, because the
anti−lock brake system cannot overcome
the laws of physics that act on your ve-
hicle:
Braking capability is dependent on tire
friction with the road surface.
Even though the anti−lock brake sys-
tem is operating, a driver cannot main-
tain full control on certain slippery road
surfaces, when cornering at high
speeds, or in violent maneuvers.
Avoid high speeds on wet roads. The
anti−lock brake system cannot elimi-
nate the risk of hydroplaning and loss
of tire friction.
Always maintain a safe distance from the
vehicle in front of you. Compared with
vehicles not fitted with an anti−lock brake
system, your vehicle may require a longer
stopping distance in the following cases:
Driving on rough, gravel or snow−cov-
ered roads.
Driving with tire chains installed.
Driving on roads where the road sur-
face is pitted or has other differences
in surface height.
ProCarManuals.com

name. SIENNA (U)
174
Ty p e A
Ty p e B
”ABS” warning light
The light comes on when the ignition key
is turned to the ”ON” position. After a few
seconds, the light will go off.
If either of the following conditions occurs,
this indicates a malfunction somewhere in
the parts monitored by the warning light
system. Contact your Toyota dealer as
soon as possible to service the vehicle.
The light does not come on as de-
scribed above, or remains on.
The light comes on while driving.
Even if the anti−lock brake system should
fail, the brake system will still operate
conventionally. However, when the ”ABS”
warning light is on (and the brake system
warning light is off), the anti−lock brake
system is not assisting brake performance
so that the wheels can lock−up during
sudden braking or braking on slippery
road surfaces. Have your vehicle checked
by your Toyota dealer as soon as pos-
sible.
Brake pad wear limit indicators
The brake pad wear limit indicators on
your disc brakes give a warning noise
when the brake pads are worn to where
replacement is required.
If you hear a squealing or scraping noise
while driving, have the brake pads
checked and replaced by your Toyota
dealer as soon as possible. Expensive ro-
tor damage can result if the pads are not
replaced when necessary.
ProCarManuals.com

name. SIENNA (U)
175
Luggage stowage precautions
When stowing luggage or cargo in the
vehicle, observe the following:
Put luggage or cargo in the luggage
compartment when at all possible. Be
sure all items are secured in place.
Be careful to keep the vehicle bal-
anced. Locating the weight as far for-
ward as possible helps maintain bal-
ance.
For better fuel economy, do not carry
unneeded weight.
CAUTION
To prevent luggage or packages
from sliding forward during braking,
do not stack anything in the lug-
gage compartment higher than the
seatbacks. Keep luggage or pack-
ages low, as close to the floor as
possible.
Never allow anyone to ride in the
luggage compartment. It is not de-
signed for passengers. They should
ride in their seats with their seat
belts properly fastened. Otherwise,
they are much more likely to suffer
serious bodily injury, in the event
of sudden braking or a collision.
Do not drive with objects left on
top of the instrument panel. They
may interfere with the driver’s field
of view. Or they may move during
sharp vehicle acceleration or turn-
ing, and impair the driver’s control
of the vehicle. In an accident they
may injure the vehicle occupants.
NOTICE
Do not load the vehicle beyond the
vehicle capacity weight specified in
Part 8.
The roof luggage carrier consists of
roof rails (1) attached to the roof and
sliding crossrails (2).
To adjust the positions of crossrails, do
this.
1. Turn the knobs counterclockwise to
loosen the crossrails.
2. Slide the crossrails to the desired posi-
tion for loading the luggages of various
sizes.
3. After adjusting, be sure to tighten the
crossrails by turning knobs clockwise.
Follow the manufacture’s instructions and
precautions when installing the attach-
ments or their equivalent.
Roof luggage carrier
ProCarManuals.com

name. SIENNA (U)
176
CAUTION
When you load cargo on the roof lug-
gage carrier, observe the following:
Place the cargo so that its weight
is distributed evenly between the
front and rear axles.
If loading long or wide cargo, never
exceed the vehicle overall length or
width. (See ”Dimensions” in Part 8
for information on your vehicle
overall length and width.)
Before driving, make sure the cargo
is securely fastened on the roof
luggage carrier.
Avoid sudden starts, sharp turns or
sudden braking.
If driving for a long distance, on
rough roads, or at high speeds,
stop the vehicle now and then dur-
ing the trip to make sure the cargo
remains in its place.
Do not exceed 50 kg (110 lb.) cargo
weight on the roof rails. However,
if the allowable cargo weight of the
cross rails is under 50 kg (110 lb.)
observe the load limit.
NOTICE
When loading the luggages, be careful
not to scratch the surface of the
moon roof.
The vehicle identification number (VIN)
is the legal identifier for your vehicle.
This number is on the left top of the
instrument panel, and can be seen
through the windshield from outside.
This is the primary identification number
for your Toyota. It is used in registering
the ownership of your vehicle.
Your Toyota’s identification—
—Vehicle identification
number
ProCarManuals.com