Chevrolet 2010 Impala Owner's Manual page 159

This feature illuminates the interior for a period of time
after the key is removed from the ignition.
The ignition must be off for delayed exit lighting to work.
When the key is removed, interior illumination activates
and remains on until one of the following occurs:
The ignition is in ON/RUN.
The power door locks are activated.
An illumination period of 20 seconds has elapsed.
If during the illumination period a door is opened, the
timed illumination period will be canceled and the
interior lamps will remain on because a door is open.
Parade mode automatically prohibits the dimming of the
instrument panel displays during the daylight while the
headlamps are on so that the displays are still able to
be seen.
The vehicle has reading lamps that also act as the
dome lamp. Press the button near each lamp to turn
them on and off.
The vehicle has map lamps on the rearview mirror.
Press the button near each lamp on the mirror to turn
the map lamps on and off.
The vehicle has Electric Power Management (EPM) that
estimates the battery's temperature and state of charge.
It then adjusts the voltage for best performance and
extended life of the battery.
When the battery's state of charge is low, the voltage
is raised slightly to quickly bring the charge back up.
When the state of charge is high, the voltage is lowered
slightly to prevent overcharging. If the vehicle has a
voltmeter gauge or a voltage display on the Driver
Information Center (DIC), you may see the voltage
move up or down. This is normal. If there is a problem,
an alert will be displayed.
The battery can be discharged at idle if the electrical
loads are very high. This is true for all vehicles. This is
because the generator (alternator) may not be spinning
fast enough at idle to produce all the power that is
needed for very high electrical loads.
4-13