Lexus 2004 GX470 Owner's Manual page 86

D Driving range mode
The distance the vehicle can travel with the remaining fuel
is calculated and displayed based on the quantity of
remaining fuel and past fuel consumption.
The driving range display indicates the approximate distance
that you can drive until the fuel gauge reaches "E". It is different
from the actual distance traveled.
The displayed value is updated every time the fuel required to
travel 0.6 miles (1 km) is consumed.
Every time you refuel the vehicle, the calculation is reset.
The actual driving range varies with driving habits and road
conditions. If fuel consumption is good, the driving range will
be longer. If fuel consumption is poor, the driving range will be
shorter.
If the low fuel level warning light comes on, refuel even if the
display indicates that the vehicle can be driven further.
GAUGES, METERS AND SERVICE REMINDER INDICATORS
D Average vehicle speed mode
Average vehicle speed is calculated and displayed based
on total driving distance and total driving time with the
engine running.
The displayed value is updated every 10 seconds.
To reset the calculations, push and hold the "RESET" button for
more than 1 second.
71