Lexus 2003 LS Owner's Manual page 69

The displayed cruise information values indicate the general
driving condition and may not always reflect precise and actual
conditions.
A Available driving distance
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When the fuel gauge is close to "F"
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When the fuel gauge is close to middle
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When the fuel gauge is close to "E"
The available driving distance is calculated and displayed
depending on the amount of remaining fuel.
A Average fuel consumption
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The average fuel consumption is calculated and displayed
based on the total driving distance and the total fuel
consumption with the engine running.
The value is updated every 10 seconds.
To begin recalculating, push the "RESET" button for about 1 to
2 seconds.
GAUGES, METERS AND SERVICE REMINDER INDICATORS
A Current fuel consumption
The current fuel consumption is calculated and displayed
based on the driving distance and the fuel consumption
per 2 second interval with the engine running.
The value is updated every 2 seconds.
If you are driving at low speeds just before stopping, the
accurate figure may not be shown.
A Average fuel consumption after refueling
The average fuel consumption after refueling is
calculated and displayed based on the total driving
distance and the total fuel consumption after refueling.
The value is updated every 10 seconds.
When refueling, be sure to stop your vehicle and turn the
ignition switch off.
The average fuel consumption could not be calculated in either
of the following cases:
A Refueled by opening the fuel filler door using the manual
lever in the trunk
A Refueled with a small quantity of gasoline
To begin recalculating, push the "RESET" button for about 1 to
2 seconds.
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