Lexus 2003 LS Owner's Manual page 64

GAUGES, METERS AND SERVICE REMINDER INDICATORS
(e) Discharge Warning Light
This light warns that the battery is being discharged.
If it comes on while you are driving, stop the vehicle, turn off the
engine, and check for the cause. Look first at the engine drive
belt.
A If it is loose or broken, the generator will not charge the
battery properly.
A If the belt is O.K., there is a problem somewhere in the
charging system.
The engine ignition will continue to operate, however, until the
battery is discharged. Turn off the air conditioning, blower,
radio, etc., and drive directly to the nearest Lexus dealer or
repair shop.
NOTICE
Do not continue driving if the engine drive belt is broken
or loose.
50
(f) Malfunction Indicator Lamp
This lamp comes on when the ignition switch is turned to
the "ON" position and goes off after the engine starts.
This means that the warning light system is operating
properly.
If the lamp remains on, or the lamp comes on while
driving, first check the following:
A Empty fuel tank
If the fuel tank is empty, refuel immediately.
A Loose fuel tank cap
If the fuel tank cap is loose, securely tighten it.
These cases are temporary malfunctions. The malfunction
indicator lamp will go off after taking several driving trips.
If the lamp will not go off even after several trips, contact your
Lexus dealer as soon as possible.
If the fuel tank is not empty or the fuel tank cap is not
loose...
A There is a problem somewhere in the engine, emission
control system, electronic throttle control system, automatic
transmission electrical system or warning light system itself.
Contact your Lexus dealer as soon as possible to service the
vehicle.
If this lamp comes on and the engine speed does not increase
with the accelerator pedal depressed, there may be a problem
somewhere in your electronic throttle control system.