Chevrolet 2003 Impala Owner's Manual page 73

At times you may notice a decrease in range. This is
normal for any remote keyless entry system. If the
transmitter does not work or if you have to stand closer
to your vehicle for the transmitter to work, try this:
e
e
e
e
Check the distance. You may be too far from your
vehicle. You may need to stand closer during
rainy or snowy weather.
Check the location. Other vehicles or objects may
be blocking the signal. Take a few steps to the
left or right, hold the transmitter higher, and
try again.
Check to determine if battery replacement or
resynchronization is necessary. See "Battery
Replacement" and "Resynchronization" under
Remote Keyless Entry System Operation on
page 2-4.
If you are still having trouble, see your dealer or a
qualified technician for service.
Remote Keyless Entry System
Operation
Using the remote keyless
entry transmitter, you can
lock and unlock your
doors or release your trunk
from about 3 feet (1 m)
up to 30 feet (9 m) away.
LOCK: Press the LOCK button to lock all the doors.
UNLOCK: Press the UNLOCK button once to unlock
the driver's door and turn on the interior lamps.
See "Illumination on Remote Activation" later in this
section for more details. Pause for about one second,
then press UNLOCK again to unlock the
passenger door.
2-4