If the keyless remote battery or the vehicle battery is dead, use the key instead of the keyless remote.

Fully insert the key and turn it.
Locking/Unlocking the Doors Using a Key
When you lock the driver’s door with a key, all the other doors lock at the same time. When unlocking, the driver’s door unlocks first. Turn the key a second time within a few seconds to unlock the remaining doors.
Models with driver information interface
You can customize the door unlock mode setting.
Customized Features
Using the Remote Transmitter
Locking a Door Without Using a KeyHonda Civic Owners Manual. Switching the Display
Using the button
Press the (display) button to
change the display.
Using the audio/information screen
Select to go to the home
screen.
Select Phone, Info, Audio, Settings, Navigation*, HondaLink, Smartphone
Connection (Apple CarPlay, Android Auto), App List, or Instrument Panel ...