Honda CLARITY Fuel Cell 2020 Owner's Manual page 15

Sounds Unique to the Fuel Cell Vehicle
When you first start driving this vehicle, you likely will hear some unfamiliar sounds, particularly when you first turn on the power system,
while driving, and just after parking. Some of these sounds are unique to this vehicle's powertrain, fuel, and climate control systems; others
are similar to sounds generated by conventional automobiles that typically are masked by louder noises absent from a vehicle of this design.
These sounds are not a cause for concern, and you will soon recognize them as normal and thus be able to detect any new or unusual noise
should one develop.
Certain sounds associated with your vehicle may be caused by:
● Pressurized intake air being released through the rear of the vehicle.
This can happen if the accelerator is released suddenly when the vehicle is under a heavy load, such as when climbing a hill.
u
● The power system warming up.
u This sound is particularly loud when temperatures are extremely low (below –4°F [–20°C]).
● Hydrogen gas flowing through the fuel line during refueling.
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