2021 HYUNDAI NEXO Fuel system

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

7-45
7
Maintenance
F
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A vehicle's electrical system is pro-
tected from electrical overload dam-
age by fuses.
This vehicle has 2 (or 3) fuse panels,
one located in the driver's side panel
bolster, the other in the fuel cell
power module compartment near the
battery. If any of your vehicle’s lights, acces-
sories, or controls do not work, check
the appropriate circuit fuse. If a fuse
has blown, the element inside the
fuse will be melted or broken.
If the electrical system does not
work, first check the driver's side
fuse panel. Before replacing a blown
fuse, turn the vehicle and all switch-
es off, and then disconnect the neg-
ative battery cable. Always replace a
blown fuse with one of the same rat-
ing.
If the replacement fuse blows, this
indicates an electrical problem. Avoid
using the system involved and imme-
diately consult an authorized
HYUNDAI dealer.
Information
Three kinds of fuses are used: blade
type for lower amperage rating, car-
tridge type, and multi fuse for higher
amperage ratings.
i
NEVER replace a fuse with any-
thing but another fuse of the
same rating.
A higher capacity fuse could
cause damage and possibly
cause a fire.
Do not install a wire or alu-
minum foil instead of the
proper fuse - even as a tem-
porary repair. It may cause
extensive wiring damage and
possibly a fire.
WARNING
Normal
■
Blade type
■ Cartridge type Blown
Normal Blown
OAEE076008
Normal
Blown
■ Multi fuse

7-48
Maintenance
Multi fuse
If the multi fuse is blown, it must be
removed as follows:
1. Turn the vehicle off.
2. Disconnect the negative batteryconnector located on the trunk.
3. Remove the fuse panel cover by pressing the tab and pulling it up.
4. Remove the nuts shown in the pic- ture above.
5. Replace the fuse with a new one of the same rating.
6. Reinstall in the reverse order of removal.
Information
If the multi fuse is blown, consult an
authorized HYUNDAI dealer.
i
OFE078022
After checking the fuse box in
the fuel cell power module com-
partment securely close the
fuse box cover inside the motor
compartment, until it clicks.
If the fuse box is not closed
properly, water may leak in side,
possibly causing a malfunction
with the electrical system.
CAUTION

7-65
7
Maintenance
Bright-metal maintenance
To remove road tar and insects,use a tar remover, not a scraper or
other sharp object.
To protect the surfaces of bright- metal parts from corrosion, apply a
coating of wax or chrome preser-
vative and rub to a high luster.
During winter weather or in coastal areas, cover the bright metal parts
with a heavier coating of wax or
preservative. If necessary, coat the
parts with non-corrosive petroleum
jelly or other protective compound.
Underbody maintenance
Corrosive materials used for ice and
snow removal and dust control may
collect on the underbody. If these
materials are not removed, acceler-
ated rusting can occur on underbody
parts such as the fuel lines, frame,
floor pan and exhaust system, even
though they have been treated with
rust protection. Thoroughly flush the vehicle under-
body and wheel openings with luke-
warm or cold water once a month,
after off-road driving and at the end
of each winter. Pay special attention
to these areas because it is difficult
to see all the mud and dirt. It will do
more harm than good to wet down
the road grime without removing it.
The lower edges of doors, rocker
panels, and frame members have
drain holes that should not be
allowed to clog with dirt; trapped
water in these areas can cause rust-
ing.
Aluminum wheel maintenance
The aluminum wheels are coated
with a clear protective finish.
Do not use abrasive cleaner, pol-
ishing compound, solvent, or
wire brushes on aluminum
wheels.
Clean the wheel when it has cooled.
Use only a mild soap or neutral detergent, and rinse thoroughly
with water. Also, clean the
wheels after driving on salted
roads.
Do not wash the wheels with high-speed car wash brushes.
Do not use any cleaners con- taining acid or alkaline deter-
gents.
NOTICE
After washing the vehicle, test
the brakes while driving slowly
to see if they have been affected
by water. If braking performance
is impaired, dry the brakes by
applying them lightly while
maintaining a slow forward
speed.
WARNING

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