2023 HYUNDAI NEXO Owners Manual

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CategoryQuestionsAnswers
Vehicle
Management (12 items)
19. What are the do-it-yourself (DIY) main-
tenance items for the FCEV?
DIY Check: Device cooling coolant, Stack cooling coolant, Brake
Fluid, Tire and Wheels
DIY Maintenance: Washer fluid, Air cleaner, Climate control air filter,
Wiper blades, Fuse, Light bulb
20. What should I be aware of when doingDIY maintenance work?Be careful not to touch the high-voltage cable (orange color),
coolant, and ion filter.
21. Tell me what the potential effects are ofparking long-term in a cold area (-20 °C
(-4 °F)) for the FCEV, and whether or
not the vehicle can startup under such
conditions.In most instances, the vehicle can get startup in cold weather with-
out any problems. However, the vehicle may not start if it is parked
with the power off for over a week in cold temperatures. In this case,
If you will not be turning on the vehicle for more than a week in cold
weather, it is recommended that you park the vehicle inside a build-
ing, if possible.
22. What parts must I not touch with
hands? For example, high-voltage
cable, ion filter, etc.?
High-voltage cable (orange color), ion filter, parts with a high voltage
warning sticker.
Also, never touch the hydrogen storage system under the tailgate,
the hydrogen supply pipe under the vehicle and the hydrogen supply
system components on the right side (based on the driver’s position)of the hood.

H36
CategoryQuestionsAnswers
Cluster /
Warning Lamp
(9 items)
23. What shall I do if the hydrogen gas leak warning light turns on on the cluster?
(Red)If the hydrogen gas leak warning light turns on during "READY" sta-
tus or in driving mode, this indicates a hydrogen gas leak inside the
vehicle. DO NOT lose your composure. Park your vehicle and turn
OFF the vehicle. Then, contact an authorized HYUNDAI dealer for
service.
24. Can I keep driving the vehicle even ifthe hydrogen gas leak warning light
turns on on the cluster?
(Red)The fuel cell stops working if hydrogen is no longer available. However,
the FCEV can run for an additional distance (About 3 km (2 miles)) in
EV mode where the vehicle runs only on battery power. Mileage in EV
mode can vary depending on the "state of charge" (SOC) of the high
voltage battery, so move your vehicle to the nearest shoulder on the
road. Then, contact an authorized HYUNDAI dealer for service.
25. While driving to a service center afterthe hydrogen gas leak warning light
turns on on the cluster, is it possible
that the vehicle catch fire if there is
something nearby to ignite the leaking
gas (cigarette butt, etc.)?
(Red)
As soon as the hydrogen gas leak warning light appears, the fuel
cell operation is disabled immediately to cut the supply of hydrogen.
This prevents the possibility of a fire occurring.
26. What should I do if a power down warn-ing light turns on?If the power down warning light turns on during "READY" status or
in driving mode, power supply to the fuel cell system is cut off. If the
warning light turns on repeatedly when restarting the vehicle after
parking your car on the safe place, please contact an authorized
HYUNDAI dealer for service.
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H37
CategoryQuestionsAnswers
Cluster /
Warning Lamp (9 items)
27. What should I do if the service warning
light turns on?If the service warning light turns on during "READY" status or in driv-
ing mode, it may indicate a malfunction in operation with any fuel cell
system. Please contact an authorized HYUNDAI dealer for service.
28. What should I do if the master warninglight turns on?If the service warning light turns on when there is a malfuction in
operation in any of the vehicle systems. Please look at the LCD dis-
play for details and contact an authorized HYUNDAI dealer for serviceif needed.
29. How much farther (roughly) can I drivemy FCEV when the fuel warning light
turns on? (Remaining mileage)You can continue driving for an additional 70~90 km (40~55 miles).
It may depend on driving mode.
30. When restarting the vehicle, the " "indicator turns on on the cluster. What does this mean?It means that the fuel cell system is working in good order and your
car is ready to drive.
31. Why does the vehicle’s hydrogen tankhave a life expectancy?
The hydrogen tank is frequently refueled with the high pressure
hydrogen gas and the number of times refueling the vehicle is limit-
ed to 5,000 times (or 15 years). The hydrogen storage system
counts the number of times the vehicle is refueled and turns on the
warning light when the vehicle is refueled for over 4,995 times.
Every time the vehicle is turned on the warning message “Replace
hydrogen tank. Maximum number of refill cycles exceeded
” is displayed on the cluster. The vehicle can be driven about 1-3
million kilometers until the vehicle is refueled 5,000 times, meaning
that the hydrogen tank is used semi-permanently under common
driving condition.

H38
CategoryQuestionsAnswers
HydrogenSystem
(7 items)
32. What happens if hydrogen in the hydro- gen tank is completely consumed?
The fuel cell stops working if hydrogen is no longer available.
However, the FCEV can run for an additional distance (About 3 km
(2 miles)) in EV mode where the vehicle runs only on battery power.
Mileage in EV mode can vary depending on the "status of charge"
(SOC) of the high voltage battery, so move your vehicle to the near-
est shoulder on the road. Then, contact an authorized HYUNDAI
dealer for service.
33. If the hydrogen gas tank is fully refu-eled, how much farther can the FCEV
run?It can travel as far as 500~600 km (300~370 miles) at a constant
vehicle speed of 80 kph (50 mph). Realistically though, this travel
distance is shorter due to normal acceleration and deceleration
when driving.
34. Which mechanism allows for the hydro-
gen gas tank to be refueled, and is it
possible to refuel the tank as much as
you need? Is it possible that the tank
may not be fully refueled?
The tank is refueled by utilizing the difference in hydrogen pressure
between the refueling station and the vehicle. When refueling, the
hydrogen gas pressure of the refueling station is higher than that of
the vehicle. The act of refueling can be stopped as desired.
Normally, the gas tank is not fully refueled with hydrogen if the sta-
tion's hydrogen pressure is not sufficiently high, or if the station sys-
tem cannot communicate with the vehicle. ❈System and the vehicle communicates the temperature and pres-
sure of hydrogen gas via wireless network.
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H39
CategoryQuestionsAnswers
HydrogenSystem
(7 items)
35. In the beginning, when driving the new vehicle, I hear hissing sounds regularly
from the hood while the vehicle is
stopped. Is this noise cause for con-
cern?
In the beginning, the purity of hydrogen in the hydrogen tank of the
new vehicle may be somewhat low. It is a normal noise which
occurs when the system discharges the hydrogen more frequently
compensating the low hydrogen purity. The fuel efficiency of the new
vehicle may be low in the beginning due to the frequent hydrogen
discharge. However, this is a normal condition. In general, the hydro-
gen purity returns to normal range after refueling 3-4 times.

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CategoryQuestionsAnswers
Hydrogen
System
(7 items)36. How should I refuel the tank with hydro- gen gas? And what should I take care of?
* Close the fuel cap and fuel filler door firmly.
* The gas tank may not be fully filled depending on the conditions ofthe hydrogen station.
* Carefully read any precautions about refueling at hydrogen gas stations.
* Be careful not to cause static electricity when touching the fuel filler with your hand. (To avoid static electricity, be sure to touch
your bare hand on something metallic as far from the fuel filler as
possible.)
* DO NOT get out of, or go into, your car while the gas tank is being refueled.
* DO NOT use any mobile device. Fire may occur due to electric current / radio wave from the mobile device.
* Make sure that the fuel cell system stops working before refueling the gas tank.
* DO NOT smoke a cigarette or strike a lighter while refueling the gas tank.
* If you need assistance with refueling the gas tank after completely consuming all the available fuel in the vehicle, please contact an
authorized HYUNDAI dealer.

H41
CategoryQuestionsAnswers
HydrogenSystem
(7 items)
37. Is it possible that water, oil, etc. may be introduced to the hydrogen gas tank via
the fuel filler? If yes, what do I need to
do to prevent this?Normally, water and oil cannot flow into the hydrogen tank via the
fuel filler, but it can flow in while refueling. Be careful not to intro-
duce any contaminants via the fuel filler.
38. While refueling the hydrogen, I hearirregular abnormal noises. Is this noise
cause for concern?
The hydrogen gas is in high pressure (70 MPa) condition when refu-
eled to the vehicle's storage tank. Therefore, you will hear the sound
of the gas flowing in the beginning. Abnormal noise is occurred due
to the gas flow because of the difference in refueling pressure, etc.depending on the gas pressure condition at the refueling station and
this is very normal.

H42
CategoryQuestionsAnswers
Fuel Cell
Stack/High VoltageBattery
(4 items)
39. What happens if hydrogen gas leaks
from the fuel cell stack?
(Red)If hydrogen gas leaks beyond what's tolerable from the fuel cell stack,
a hydrogen sensor installed in the system detects the leak and in
response, turns ON the hydrogen gas leak warning light in the cluster.
40. Can the fuel cell stack explode or burnout due to overheating?The fuel cell stack passed a high temperature test and is deemed
safe, so it is unlikely to explode.
41. Which symptoms occur if the fuel cellsystem malfunctions?
If the fuel cell system malfunctions, warning lights specific to the
actual problem appear on the LCD display. When this happens, the
vehicle speed may be limited, or the fuel cell system may shut
down. DO NOT lose your composure if this happens. Park your vehi-
cle and turn OFF the vehicle. Then, contact an authorized HYUNDAI
dealer for service.
42. Is the recharge performance of the high
voltage battery reduced depending on its length of use? Like any vehicle component, the high voltage battery will decrease
in performance as it ages over time. However, the high voltage bat-
tery of the FCEV is durable enough to work at peak performance
beyond the warranty period.
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