Lexus 2004 LS430 Owner's Manual page 57

The operational range of the wireless remote control is
approximately 1 m (3 ft.). The effective range may vary with
different conditions. To activate the wireless remote control
without fail, do it approximately 1 m (3 ft.) from your Lexus.
In the following cases, the battery in the key may be
discharged. If this is a case, replace the battery using a special
screwdriver. For the key of Type A, we recommend that you
have the battery replaced by your Lexus dealer to prevent the
key from being damaged.
D The remote control does not work.
D The operational range of wireless remote control becomes
extremely short.
D The indicator light on the key is dimmed or does not come
on.
For the replacement of the battery of the Type B key, see
"Replacing the battery" on page 44. You can also have the
battery of the key replaced by your Lexus dealer.
If you lose the wireless function key, contact your Lexus dealer
as soon as possible to avoid the possibility of theft, or an
accident. (See "If you lose your keys or lock yourself out" on
page 434.)
If your vehicle is equipped with smart key system, you can use
up to 5 master keys and 3 sub keys for the same vehicle. In
case of the vehicle not equipped with smart key system, up to
4 master keys are available. Contact your Lexus dealer for
detailed information.
KEYS AND DOORS
The wireless remote control function key is an electronic
component. Observe the following instructions in order
not to cause damage to the key.
D Do not leave the wireless remote control function key in
places where the temperature becomes high such as on the
dashboard.
D Do not disassemble it.
D Avoid knocking it hard against other objects or dropping it.
D Avoid putting it in water.
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