2021 HYUNDAI NEXO fuel pressure

7-16
Maintenance
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The high-pressure cooling system
has a reservoir filled with year-round
antifreeze coolant. The reservoir is
filled at the factory.
Check the antifreeze protection and
coolant level at least once a year, at
the beginning of the winter season
and before traveling to a colder cli-
mate.Checking the Coolant Level
Check the condition and connections
of all cooling system hoses and
heater hoses. Replace any swollen
or deteriorated hoses.
When replacing any part of the cool-
ing system there may be loss of
coolant. In that case, fill with an
exclusive coolant for the fuel cell.
When replacing the ion filter car-
tridge, replace the whole stack
coolant.
The coolant level should be filled
between F (MAX) and L (MIN) marks
on the side of the coolant reservoir
when the fuel cell power module is
cool. If the stack cooling coolant level is
low, add enough exclusive coolant
for fuel cell stack to provide protec-
tion against freezing and corrosion in
the authorized HYUNDAI dealer.
In addition, whenever replacing the
ion filter cartridge, add enough exclu-
sive coolant for fuel cell stack.
OFE078005

Stack cooling coolant
When adding stack coolingcoolant, use only exclusive coolant
for fuel cell stack in authorized
HYUNDAI dealer and never mix
any water or liquid.
An improper coolant mixture can result in severe malfunction or
electric devices damage.
If the vehicle is damaged by adding unspecified liquid except exclusive
coolant for fuel cell stack, it will not
be covered by the warranty.
7-17
7
Maintenance
Never remove the
radiator cap or the
drain plug while the
radiator is hot. Hot
coolant and steam
may blow out under pressure,
causing serious injury.
WARNING
OFE078006
Turn the vehicle off and wait
until the parts in the fuel cell
power module compartment
cools down. Use extreme care
when removing the cap. Wrap a
thick towel around it, and turn it
counterclockwise slowly to the
first stop. Step back while the
pressure is released from the
cooling system. When you are
sure all the pressure has been
released, press down on the
cap, using a thick towel, and
continue turning counterclock-
wise to remove it.

The electric motor for the cooling fan
is controlled by coolant temperature,
refrigerant pressure and vehicle
speed. As the coolant temperature
decreases, the electric motor will
automatically shut off. This is a nor-
mal condition.
Changing Coolant
For the fuel cell stack, an exclusive
coolant must be used . When chang-
ing the fuel cell stack coolant, we
recommend that coolant be changed
by an authorized HYUNDAI dealer
according to the Maintenance
Schedule at the beginning of this
chapter.To prevent damage to parts in the
fuel cell power module compart-
ment, put a thick towel around the
coolant cap before refilling the
coolant to prevent the coolant
from overflowing into parts in the
fuel cell power module compart-
ment.
NOTICE
7-18
Maintenance
The electric motor for
the cooling fan may
continue to operate
or start up when the
vehicle is not running
and can cause serious injury.
Keep hands, clothing and tools
away from the rotating fan
blades of the cooling fan.
WARNING
Do not use coolant or antifreeze
in the washer fluid reservoir.
Coolant can severely obscure
visibility when sprayed on the
windshield and may cause loss
of vehicle control resulting in an
accident.
Coolant may also cause dam-
age to paint and body trim.
WARNING
Do not mix-up the caps of
device cooling coolant and
stack cooling coolant because
the fluid material is different. If
the cap is mixed, the fuel cell
system may be damage.
We recommend that you con-
sult an authorized HYUNDAI
dealer.
CAUTION

7-29
7
Maintenance
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Tire Care
For proper maintenance, safety, and
maximum fuel economy, you must
always maintain recommended tire
inflation pressures and stay within
the load limits and weight distribution
recommended for your vehicle.

ALWAYS replace tires with the
same size as each tire that
was originally supplied with
this vehicle. Using tires and
wheels other than the recom-
mended sizes could cause
unusual handling characteris-
tics, poor vehicle control, or
negatively affect your vehi-
cle's Anti-Lock Brake System
(ABS) resulting in a serious
accident.
Tire failure may cause loss of
vehicle control resulting in an
accident. To reduce risk of
SERIOUS INJURY or DEATH,
take the following precautions:
Inspect your tires monthly for
proper inflation as well as
wear and damage.
The recommended cold tire
pressure for your vehicle can
be found in this manual and
on the tire label located on the
driver's side center pillar.
Always use a tire pressure
gauge to measure tire pres-
sure. Tires with too much or
too little pressure wear
unevenly causing poor han-
dling.
Replace tires that are worn,
show uneven wear, or are
damaged. Worn tires can
cause loss of braking effec-
tiveness, steering) control, or
traction.
WARNING

7-31
7
Maintenance
Check Tire Inflation Pressure
Check your tires once a month or
more.
How to check
Use a good quality tire pressure
gauge to check tire pressure. You
can not tell if your tires are properly
inflated simply by looking at them.
Radial tires may look properly inflat-
ed when they are under-inflated.
Remove the valve cap from the tire
valve stem. Press the tire gauge firm-
ly onto the valve to get a pressure
measurement. If the cold tire inflation
pressure matches the recommended
pressure on the tire and loading
information label, no further adjust-
ment is necessary. If the pressure is
low, add air until you reach the rec-
ommended pressure. Make sure to
put the valve caps back on the valve
stems. Without the valve cap, dirt or
moisture could get into the valve
core and cause air leakage. If a valve
cap is missing, install a new one as
soon as possible.If you overfill the tire, release air by
pushing on the metal stem in the
center of the tire valve. Recheck the
tire pressure with the tire gauge. Be
sure to put the valve caps back on
the valve stems. Without the valve
cap, dirt or moisture could get into
the valve core and cause air leakage.
If a valve cap is missing, install a new
one as soon as possible.
Under-inflation results in
excessive wear, poor handling
and reduced fuel economy.
Wheel deformation is also
possible. Keep your tire pres-
sures at the proper levels. If a
tire frequently needs refilling,
have it checked by an author-
ized HYUNDAI dealer.
Over-inflation produces a
harsh ride, excessive wear at
the center of the tire tread,
and a greater possibility of
damage from road hazards.
CAUTION

7-39
7
Maintenance
Bead
The tire bead contains steel wires
wrapped by steel cords that hold the
tire onto the rim.
Bias Ply Tire
A pneumatic tire in which the plies
are laid at alternate angles less than
90 degrees to the centerline of the
tread.
Cold Tire Pressure
The amount of air pressure in a tire,
measured in pounds per square inch
(psi) or kilopascals (kPa) before a tire
has built up heat from driving.
Curb Weight
This means the weight of a motor
vehicle with standard and optional
equipment including the maximum
capacity of fuel, oil and coolant, but
without passengers and cargo.
DOT Markings
A code molded into the sidewall of a
tire signifying that the tire is in com-
pliance with the U.S. Department of
Transportation motor vehicle safety
standards. The DOT code includes
the Tire Identification Number (TIN),
an alphanumeric designator which
can also identify the tire manufactur-
er, production plant, brand and date
of production.
GVWR
Gross Vehicle Weight Rating
GAWR FRT
Gross Axle Weight Rating for the
Front Axle.
GAWR RR
Gross Axle Weight Rating for the
Rear axle.
Intended Outboard Sidewall
The side of an asymmetrical tire, that
must always face outward when
mounted on a vehicle.
Kilopascal (kPa)
The metric unit for air pressure.
Light truck(LT) tire
A tire designated by its manufacturer
as primarily intended for use on light-
weight trucks or multipurpose pas-
senger vehicles.
Load ratings
The maximum load that a tire is rated
to carry for a given inflation pressure.
Load Index
An assigned number ranging from 1
to 279 that corresponds to the load
carrying capacity of a tire.

7-63
7
Maintenance
Do not use strong soap, chemi-cal detergents or hot water, and
do not wash the vehicle in direct
sunlight or when the body of the
vehicle is warm.
Be careful when washing the side windows of your vehicle.
Especially, with high-pressure
water, water may leak through
the windows and wet the interi-
or.
To prevent damage to the plastic parts, do not clean with chemi-
cal solvents or strong deter-
gents. Water washing in the fuel cell
power module compartment
including high pressure water
washing may cause the failure
of electrical circuits located in
the fuel cell power module com-
partment.
Never allow water or other liquids to come in contact with electri-
cal/electronic components inside
the vehicle as this may damage
them. Matte paint finish vehicle
Automatic car wash which uses
rotating brushes should not be
used as this can damage the sur-
face of your vehicle. A steam
cleaner which washes the vehicle
surface at high temperature may
result the oil to adhere and leave
stains that is difficult to remove.
Use a soft cloth (e.g. microfiber
towel or sponge) when washing
your vehicle and dry with a
microfiber towel. When you hand
wash your vehicle, you should not
use a cleaner that finishes with
wax. If the vehicle surface is too
dirty (sand, dirt, dust, contami-
nant, etc.), clean the surface with
water before washing the car.
NOTICE
NOTICE
NOTICE
OFE078045N

Introduction of FCEV .........................................................H2
The components of FCEV..................................................H3
Fuel cell stack ...................................................................................H4
FCEV system module .......................................................................H4
High pressure hydrogen storage tanks ......................................H5
Battery system..................................................................................H5
Features of FCEV .............................................................H10
How to Start the Vehicle ..............................................................H10
How to Stop the Vehicle ..............................................................H11
Virtual Engine Sound System......................................................H11
Fuel filler door ................................................................................H12
Warning and indicator lights .......................................................H15
LCD Display Messages ..................................................................H16
FCEV mode.......................................................................................H21
When the high voltage battery is weak ...................................H25
If the 12 volt battery is discharged...........................................H25
Emergency while driving ..............................................................H26
Customer Q&A Guide .......................................................H30
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FCEV : Fuel Cell Electric Vehicle