Chevrolet 2002 Impala Owner's Manual page 163

Low Oil Pressure
United States
This message is displayed when the engine oil pressure
is low. A chime will sound continuously, also. See "Low
Oil Pressure Light" earlier in this section.
Low Eng Oil Level
Canada
This message is displayed for 60 seconds at the start of
each ignition cycle when the engine oil level is low.
Four chimes will also sound.
When the ignition is turned off, this message will be
displayed again for three seconds to remind you that
your engine oil level is low. Be sure to have your vehicle
serviced right away.
See "Engine Oil" in the Index on how to check the oil
level and for what type of oil to add.
United States Canada
2-97