Honda 2011 CIVIC COUPE Owner's Manual page 340

Checking the Battery
If you need to connect the battery to
a charger, disconnect both cables to
prevent damaging your vehicle's
electrical system. Always disconnect
the negative ( ) cable first, and
reconnect it last.
The battery gives off explosive
hydrogen gas during normal
operation.
A spark or flame can cause the
battery to explode with enough
force to kill or seriously hurt you.
Wear protective clothing and a
face shield, or have a skilled
technician do the battery
maintenance.
334
If your vehicle's battery is
disconnected or goes dead, the audio
system may disable itself. The next
time you turn on the radio, you will
see ''ENTER CODE'' in the
frequency display. Use the preset
buttons to enter the code (see page
).
221
If your vehicle's battery is
disconnected, or goes dead, the time
setting may be lost. To reset the time,
see page 222 .
On models with navigation system
The navigation system will also
disable itself. The next time you turn
on the ignition switch, the system
will require you to enter a PIN
before it can be used. Refer to the
navigation system manual.