2003 Honda Civic Owner's Manual - Page 226

Battery If you need to connect the battery to a charger, disconnect both cables to prevent damage to the car's electrical system. Charging the battery with the cables connected can seriously damage your car's electronic controls. Detach the battery cables bef ore connecting the battery to a charger. Standard for HX, LX and EX models in the U.S., and LX and Si models in Canada 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 mechanic do the battery maintenance. If the terminals are severely corroded, clean them with baking soda and water. Then use a wrench to loosen and remove the cables from the terminals. Always disconnect the negative ( ) cable first and reconnect it last. Clean the battery terminals with a terminal cleaning tool or wire brush. Reconnect and tighten the cables, then coat the terminals with grease. If your car's battery is disconnected or goes dead, the audio system will disable itself. The next time you turn on the radio you will see '' '' in the frequency display. Use the Preset buttons to enter the five-digit code (see page 149 ). Maintenance 225