Honda 1998 Prelude Owner's Manual page 191

Battery
If your vehicle's battery is discon-
nected or goes dead, the audio
system will disable itself. The next
time you turn on the radio you will
see "Code" in the frequency display.
Use the Preset buttons to enter the
five-digit code (see page 117).
NOTICE
Charging the battery with the cables
connected can seriously damage your
vehicle's electronic controls. Detach
the battery cables before connecting
the battery to a charger.
Maintenance