Toyota Lexusc Owner's Handbook Manual page 471

STARTING AND DRIVING
D Shift into the "2" (second range) position. The transmission
will downshift to second gear when the vehicle speed is or
becomes lower than 83 km/h (52 mph) and more powerful
engine braking than that of the "3" (third range) position will
be enabled.
If you drive in the "D" position: Shift the selector lever to
the "S" position and shift the lever down to the "-" position
twice to select "2" (second range).
If you drive in the "S" position: Shift the selector lever
down to the "-" position to select "2" (second range).
D Shift into the "1" (first range) position. The transmission will
downshift to first gear when the vehicle speed is or becomes
lower than 39 km/h (24 mph) and maximum engine braking
will be enabled.
If you drive in the "D" position: Shift the selector lever to
the "S" position and shift the lever down to the "-" position
three times to select "1" (first range).
If you drive in the "S" position: Shift the selector lever
down to the "-" position to select "1" (first range).
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CAUTION
Be careful when downshifting on a slippery surface.
The abrupt change in engine speed could cause the
vehicle to spin or skid.