Honda Civic Owners Manual: Audio System Theft Protection
The audio system is disabled when it is disconnected from the power source, such as when the battery is disconnected or goes dead. In certain conditions, the system may display a code entry screen. If this occurs, reactivate the audio system.
Reactivating the audio system
1. Turn the ignition switch to ON 
*1.
2. Turn on the audio system.
3. Press and hold the audio system power button for more than two seconds.
The audio system is reactivated when the audio control unit establishes a connection with the vehicle control unit. If the control unit fails to recognize the audio unit, you must go to a dealer and have the audio unit checked.
USB Port(s)
Install the iPod USB connector or the USB flash
drive to the front USB port.
Models with color audio system
The USB port (1.0A) is for playing audio
files on a USB flash drive and connecti ...
Audio Remote Controls
Allow you to operate the audio system while driving
SOURCE Button
Cycles through the audio modes as follows:
FM AM
USB iPod
Bluetooth’ Audio
+ - (Volume) Buttons
Press +: To increase the ...
See also:
Honda Civic Owners Manual. Emissions Testing
Testing of Readiness Codes
Your vehicle has readiness codes as part of the onboard self diagnostic
system.
Some States use these codes for testing to verify whether your vehicle's
emissions
components are working properly.
The codes may not be read properly if testing is performed just a ...