2021 HYUNDAI TUCSON HYBRID ECU

01
1-5
Unleaded
Your new vehicle is designed to use only unleaded fuel having an octane
number((R+M)/2) of 87 (Research Octane Number 91) or higher. (Do not use methanol
blended fuels)
Your new vehicle is designed to obtain maximum performance with UNLEADED FUEL,
as well as minimize exhaust emissions and spark plug fouling.
NOTICE
To prevent damage to the engine and engine components, never add any fuel
system cleaning agents to the fuel tank other than what has been specified.
Consult an authorized HYUNDAI dealer for additional information.
WARNING
• Do not “top off” after the nozzle automatically shuts off when refueling.
• Always check that the fuel cap is installed securely to prevent fuel spillage in the
event of an accident.
Gasoline containing alcohol and methanol
Gasohol, a mixture of gasoline and ethanol (also known as grain alcohol) are being
marketed along with or instead of leaded or unleaded gasoline. For example, “E15” is a
gasohol comprised of 15% ethanol and 85% gasoline.
Do not use gasohol containing more than 10% ethanol, and do not use gasoline or
gasohol containing any methanol. Either of these fuels may cause drivability problems
and damage to the fuel system, engine control system and emission control system.
Discontinue using gasohol of any kind if drivability problems occur.
“E85” fuel is an alternative fuel comprised of 85 percent ethanol and 15 percent
gasoline, and is manufactured exclusively for use in Flexible Fuel Vehicles. “E85” is
not compatible with your vehicle. Use of “E85” may result in poor engine performance
and damage to your vehicle’s engine and fuel system. HYUNDAI recommends that
customers do not use fuel with an ethanol content exceeding 15 percent.
NOTICE
To prevent damage to your vehicle’s engine and fuel system:
• Never use gasohol which contains methanol.
• Never use gasohol containing more than 15% ethanol.
• Never use leaded fuel or leaded gasohol.
• Never use “E85” fuel.
Your New Vehicle Limited Warranty does not cover damage to the fuel system or any
performance problems caused by the use of “E85” fuel.
FUEL REQUIREMENTS

2-7
02
„„Smartstream G 1.6 T-GDi HEV
The actual engine compartment in the vehicle may differ from the illustration.
ONX4EH090001
1. ECU
2. Engine coolant reservoir .......................9-17
3. Engine coolant reservoir cap ................9-17
4. Inverter coolant reservoir......................9-17
5. Brake fluid reservoir .............................9-20
6. Air cleaner .............................................9-22
7. Engine oil filler cap ................................9-15
8. Engine oil dipstick .................................9-15
9. Windshield washer fluid reservoir ........9-21
10. Fuse box .................................................9-41
11. Invert coolant reservoir cap ..................9-17
ENGINE COMPARTMENT

Seats & Safety System
3-12
ONX4H030004
5. To use the rear seat, lift and pull the
seatback backward by pulling the
folding lever or the strap. Pull the
seatback firmly until it clicks into
place. Make sure the seatback is
locked in place.
6.
Re

turn the rear seat belt to the proper
position.
WARNING
When returning the rear seatback from
a folded to an upright position, hold the
seatback and return it slowly. Ensure
that the seatback is completely locked
into its upright position by pushing on
the top of the seatback. In an accident
or sudden stop, the unlocked seatback
could allow cargo to move forward with
great force and enter the passenger
compartment, which could result in
serious injury or death.
WARNING
Do not place objects in the rear seats,
since they cannot be properly secured
and may hit vehicle occupants in a
collision causing serious injury or death.
WARNING
Make sure the engine is off, the gear
shifted to P (Park), and the parking
brake is securely applied whenever
loading or unloading cargo. Failure
to take these steps may allow the
vehicle to move if the shift button
is inadvertently pressed to another
position.
CAUTION
• Be careful when loading cargo
through the rear passenger seats
to prevent damage to the vehicle
interior.
• When cargo is loaded through the
rear passenger seats, ensure the
cargo is properly secured to prevent
it from moving while driving.
WARNING
Cargo should always be secured to
prevent it from being thrown about the
vehicle in a collision and causing injury
to the vehicle occupants. Do not place
objects in the rear seats, since they
cannot be properly secured and may hit
the front seat occupants in a collision.

03
3-23
This section describes how to use the
seat belts properly. It also describes
some of the things not to do when using
seat belts.
Seat belt safety precautions
Always fasten your seat belt and make
sure all passengers have fastened their
seat belts before starting any trip. Air
bags are designed to supplement the
seat belt as an additional safety device,
not a replacement. Most countries
require all occupants of a vehicle to wear
seat belts.
WARNING
Seat belts must be used by ALL
passengers whenever the vehicle is
moving. Take the following precautions
when adjusting and wearing seat belts:
• Children under the age of 13 should
be properly restrained in the rear
seats.
• Never allow children to ride in the
front passenger seat, unless the air
bag is deactivated. If a child is seated
in the front passenger seat, move
the seat as far back as possible and
properly restrain them in the seat.
• NEVER allow an infant or child to be
carried on an occupant’s lap.
• NEVER ride with the seatback
reclined when the vehicle is moving.
• Do not allow children to share a seat
or seat belt.
• Do not wear the shoulder belt under
your arm or behind your back. •
NEVER wear a seat belt over fragile
objects. If there is a sudden stop or
impact, the seat belt can damage it.
• Do not use the seat belt if it is
twisted. A twisted seat belt will not
protect you properly in an accident.
• Do not use a seat belt if the webbing
or hardware is damaged.
• Do not latch the seat belt into the
buckles of other seats.
• NEVER unfasten the seat belt
while driving. This may cause loss
of vehicle control resulting in an
accident.
• Make sure there is nothing in the
buckle interfering with the seat belt
latch mechanism. This may prevent
the seat belt from fastening securely.
• No modifications or additions
should be made by the user which
will either prohibit the seat belt
adjusting devices from operating to
remove slack, or prohibit the seat
belt assembly from being adjusted to
remove slack.
WARNING
Damaged seat belts and seat belt
assemblies will not operate properly.
Always replace:
• Frayed, contaminated, or damaged
webbing.
• Damaged hardware.
• The entire seat belt assembly after it
has been worn in an accident, even
if damage to webbing or assembly is
not apparent.
seat belts

03
3-31
Larger children
Children under age 13 and who are
too large for a booster seat should
always occupy the rear seat and use the
available lap/shoulder belts. A seat belt
should lie across the upper thighs and
be snug across the shoulder and chest
to restrain the child safely. Check belt fit
periodically. A child’s squirming could
put the belt out of position. In the event
of an accident, children are afforded the
best safety restrained by a proper Child
Restraint System in the rear seats.
If a larger child over age 13 must be
seated in the front seat, the child must
be securely restrained by the available
lap/shoulder belt and the seat should be
placed in the rearmost position.
If the shoulder belt portion slightly
touches the child’s neck or face, try
placing the child closer to the center
of the vehicle. If the shoulder belt still
touches their face or neck, they need to
be returned to an appropriate booster
seat in the rear seat.
WARNING
• Always make sure larger children’s
seat belts are worn and properly
adjusted.
• NEVER allow the shoulder belt to
contact the child’s neck or face.
• Do not allow more than one child to
use a single seat belt.
Seat belt use and injured people
A seat belt should be used when an
injured person is being transported.
Consult a physician for specific
recommendations.
One person per belt
Two people (including children) should
never attempt to use a single seat belt.
This could increase the severity of
injuries in case of an accident.
Do not lie down
Sitting in a reclined position when the
vehicle is in motion can be dangerous.
Even when buckled up, the protections
of your restraint system (seat belts
and/or air bags) is greatly reduced by
reclining your seatback.
Seat belts must be snug against your
hips and chest to work properly.
During an accident, you could be thrown
into the seat belt, causing neck or other
injuries.
The more the seat back is reclined, the
greater the chance for the passenger’s
hips to slide under the lap belt or the
passenger’s neck to strike the shoulder
belt.
WARNING
• NEVER ride with a reclined seatback
when the vehicle is moving.
• Riding with a reclined seatback
increases your chance of serious
or fatal injuries in the event of a
collision or sudden stop.
• Driver and passengers should always
sit well back in their seats, properly
belted, and with the seatbacks
upright.

03
3-33
Our recommendation: Children
always in the rear
WARNING
Always properly restrain children in the
vehicle. Children of all ages are safer
when restrained in the rear seat. A child
riding in the front passenger seat can
be forcefully struck by an inflating air
bag resulting in SERIOUS INJURY or
DEATH.
Children under age 13 should always
ride in the rear seats and must always be
properly restrained to minimize the risk
of injury in an accident, sudden stop or
sudden maneuver.
According to accident statistics, children
are safer when properly restrained in the
rear seats than in the front seat. Even
with air bags, children can be seriously
injured or killed. Children too large for a
Child Restraint System must use the seat
belts provided.
All 50 states have child restraint laws
which require children to travel in
approved Child Restraint Systems.
The laws governing the age or height/
weight restrictions at which seat belts
can be used instead of Child Restraint
System differs among countries, so
you should be aware of the specific
requirements in your country, and where
you are travelling.Child Restraint Systems must be properly
installed in the vehicle seat. Always use
a commercially available Child Restraint
System that meets the requirements
of the Federal Motor Vehicle Safety
Standards (FMVSS 213).
Child Restraint Systems are generally
designed to be secured in a vehicle seat
by lap belt portion of a lap/shoulder belt,
or by a LATCH system in the rear seats of
the vehicle.
Child Restraint System (CRS)
Infants and younger children must be
restrained in an appropriate rearward-
facing or forward-facing CRS that has
first been properly secured to the seat
of the vehicle. Read and comply with
the instructions for installation and use
provided by the manufacturer of the
Child Restraint System.
WARNING
•
NEVER install a child or infant
restraint in the front passenger's
seat.
• Always properly secure the child
restraint to a rear seat of the vehicle.
• Always follow the child restraint
system manufacturer's instructions
for installation and use.
• Always properly restrain your child in
the child restraint.
• If the vehicle head restraint prevents
proper installation of a child seat
(as described in the child restraint
system manual), the head restraint of
the respective seating position shall
be readjusted or entirely removed.
• Do not use an infant carrier or a
child safety seat that "hooks" over
a seatback, it may not provide
adequate protection in an accident.
• After an accident, have an authorized
HYUNDAI dealer check the child
restraint system, seat belts, tether
anchors and lower anchors.
Child RestRaint sys tem (CRs)

Seats & Safety System
3-36
Installing a Child Restraint
System (CRS)
WARNING
Before installing your Child Restraint
System always:
Read and follow the instructions
provided by the manufacturer of the
Child Restraint System.
Failure to follow all warnings and
instructions could increase the risk of
the SERIOUS INJURY or DEATH if an
accident occurs.
WARNING
If the vehicle head restraint prevents
proper installation of a Child Restraint
System, the head restraint of the
respective seating position shall be
readjusted or entirely removed.
After selecting a proper Child Restraint
System for your child and checking that
the Child Restraint System fits properly
on the seating position, there are three
general steps for a proper installation:
• Properly secure the Child Restraint
System to the vehicle. All Child
Restraint Systems must be secured
to the vehicle with the lap belt or lap
part of a lap/shoulder belt or with
the ISOFIX top-tether and/or ISOFIX
anchorage and/or with the support
leg. •
Make sure the Child Restraint System
is firmly secured. After installing a
Child Restraint System to the vehicle,
push and pull the seat forward and
from side-to-side to verify that it is
securely attached to the seat. A Child
Restraint System secured with a seat
belt should be installed as firmly as
possible. However, some side-to-side
movement can be expected.
When installing a Child Restraint
System, adjust the vehicle seat and
seatback (up and down, forward
and rearward) so that your child fits
in the Child Restraint System in a
comfortable manner.
• Secure the child in the Child
Restraint System. Make sure the
child is properly strapped in the Child
Restraint System according to the
Child Restraint System manufacturer’s
instructions.
CAUTION
A Child Restraint System in a closed
vehicle can become very hot. To prevent
burns, check the seating surface and
buckles before placing your child in the
Child Restraint System.

03
3-37
Lower Anchors and Tether for
Children (LATCH System)
The LATCH system holds a Child
Restraint System during driving and in
an accident. This system is designed
to make installation of the Child
Restraint System easier and reduce
the possibility of improperly installing
your Child Restraint System. The LATCH
system uses anchors in the vehicle and
attachments on the Child Restraint
System. The LATCH system eliminates
the need to use seat belts to secure the
Child Restraint System to the rear seats.
Lower anchors are metal bars built into
the vehicle. There are two lower anchors
for each LATCH seating position that will
accommodate a Child Restraint System
with lower attachments.
To use the LATCH system in your vehicle,
you must have a Child Restraint System
with LATCH attachments.
The Child Restraint System manufacturer
will provide you with instructions on how
to use the Child Restraint System with its
attachments for the lower anchors.
ONX4030035
Lower anchors have been provided in
the left and right outboard rear seating
positions. Their locations are shown
in the illustration. There are not lower
anchors provided for the center rear
seating position.
WARNING
Do not attempt to install a Child
Restraint System using lower anchors in
the rear center seating position. There
are no lower anchors provided for this
seat. Using the outboard seat anchors
can damage the anchors which may
break or fail in a collision resulting in
serious injury or death.