2006 Lexus GS430 engine

STARTING AND DRIVING
3565. Release the parking brake and brake pedal. Depress
the accelerator pedal slowly for smooth starting.
In normal cruising, the vehicle will start in first gear and
automatically shift up to the most suitable gear. On inclines,
declines or
winding roads, etc., the vehicle shifts up and down
automatically according to the running conditions to obtain the
suitable driving power and engine braking.
If you need to accelerate rapidly while driving, depress the
accelerator pedal to the full throttle position. This provides
more acceleration by automatically downshifting the
transmission to the next lower gear or beyond, depending on
the vehicle speed.
If engine braking is needed, such as in descending a long hill,
see “(c) Using engine braking”. 
AI (Artificial Intelligence) shifting control
AI shifting control selects the most suitable shift range
automatically according to the driver’s operation and
driving condition.
AI shifting control operates automatically with the
selector lever in the “D” position. When the lever is moved
to the “S” position, this function will be canceled.
Shifting control on the slope: On inclines, you can drive
smoothly with reduced shifting quantity. On declines, the
vehicle will shift down automatically to obtain optimum engine
braking and reduce the driver’s foot braking load.
Automatic shifting point change control: The automatic
shifting point control is controlled in the following way to
respond to the driver’s operation.
 When the accelerator is depr essed quickly, the vehicle
downshifts rapidly in order to improve acceleration.
 When the accelerator is q uickly released, the gear position
is maintained in order to improve engine braking and
reacceleration capabilities.
 During hard deceleration the vehicle downshifts rapidly in
order to improve engine braking and reacceleration
capabilities.

STARTING AND DRIVING
358“4” (fourth range): The most suitable gear is automatically
selected between
first and fourth gears according to vehicle
speed and driving conditions. In the “4” (fourth range)
position, the automatic transmission system will select the
most suitable gear to handle current running conditions
such as hill climbing, hard towing, etc.
“3” (third range): The most suitable gear is automatically
selected between first and third gears according to vehicle
speed and driving conditions. This range is best used when
stronger engine braking is necessary.
“2” (second range): First or second gear will automatically
be selected according to vehicle speed and driving
conditions. This range is to be used when engine braking
stronger than that of the “3” (third range) position is
necessary.
“1” (first range): This gear is fixed in first regardless of
vehicle speed or driving conditions. This range is to be used
when maximum engine braking is necessary.
If you attempt to downshift the transmission when it is not
possible to downshift due to high vehicle speed, a warning tone
sounds twice. 
Maximum allowable speeds
To get on a highway or to pass slower traffic, maximum
acceleration may be necessary. Make sure you observe the
following maximum allowable speeds in each range:
range km/h (mph)
GS430: 1 57 (35)
2 97 (60)
3 141 (88)
range km/h (mph)
GS300 (2WD): 1 54 (33)
2 93 (58)
3 137 (85)
range km/h (mph)
GS300 (4WD): 1 52 (32)
2 90 (56)
3 131 (81)
NOTICE
Do not downshift if you are going faster than the
maximum allowable speed for the next lower range.

STARTING AND DRIVING
359

“S” mode indicator light
“S” mode allows you to use the shift range positions.
The “S” mode indicator light comes on when the selector
lever is shifted into the “S” position. When the “S” mode
indicator light does not come on even with the selector lever
moved to the “S” position, there may be a problem
somewhere in the system. Have your vehicle
checked/repaired by your Lexus dealer as soon as
possible. In this case, you can drive in the same condition
as in the “D” position.
(c) Using engine braking
G31027
 “S” mode position
To use the braking power of the engine, downshift the range in
the “S” mode position as follows:
 Shift into the “5” (fifth range) position. The transmission will
downshift to fifth gear and engine braking will be enabled.
If you drive in the “D” position: Shift the selector lever to
the “S” position and “5” (fifth range) will automatically \
be
selected.
If you drive in the “S” position: Shift the selector lever
down to the “–” position by selecting the “5” (fifth ran\
ge).

STARTING AND DRIVING
360When
the cruise control is being used, even if you downshift
from “D” or “6” (sixth range) to “5” (fifth range)\
, engine
braking will not be enabled because the cruise control is not
cancelled. For vehicle speed reduction, see page 394.
Vehicles with the dynamic radar cruise control —
When the cruise control is being used in the conventional
(fixed speed) cruise control mode or in the
vehicle −to−vehicle distance control mode, even if you
downshift from “D” or “6” (sixth range) to “5” (fif\
th range),
engine braking will not be enabled because the cruise
control is not cancelled. For vehicle speed reduction, see
pages 416 and 404.
 Shift into the “4” (fourth range) position. The transmission
will downshift to fourth gear when the vehicle speed is or
becomes lower than the speed listed below and more
powerful engine braking will be enabled.
GS430 193 km/h (120 mph)
GS300 (2WD) 187 km/h (116 mph)
GS300 (4WD) 178 km/h (111 mph)
If you drive in the “D” position: Shift the selector lever to
the “S” position and shift the lever down to the “–” posi\
tion
once to select “4” (fourth range). However, when you move
the lever to the “S” position while the AI shifting control is
operating, the first shift range will be “5” (fifth range), “4”
(fourth range) or “3” (third range) because the suitable shift
range is selected depending on the driving condition.
If you drive in the “S” position: Shift the selector lever
down to the “–” position to select the “4” (fourth range\
). When
the cruise control is being used, even if you downshift
from “D” or “5” (fifth range) to “4” (fourth range)\
, engine
braking will not be enabled because the cruise control is not
cancelled. For vehicle speed reduction, see page 394.
Vehicles with the dynamic radar cruise control —
When the cruise control is being used in the conventional
(fixed speed) cruise control mode or in the
vehicle −to−vehicle distance control mode, even if you
downshift from “D” or “5” (fifth range) to “4” (fourth range),
engine braking will not be enabled because the cruise
control is not cancelled. For vehicle speed reduction, see
pages 416 and 404.
 Shift into the “3” (third range) position. The transmission will
downshift to third gear when the vehicle speed is or
becomes lower than the speed listed below and more
powerful engine braking will be enabled.
GS430 144 km/h (90 mph)
GS300 (2WD) 135 km/h (84 mph)
GS300 (4WD) 129 km/h (80 mph)
If you drive in the “D” position: Shift the selector lever to
the “S” position and shift the lever down to the “–” posi\
tion
twice to select the “3” (third range). However, when you
move the lever to the “S” position while the AI shifting control
is operating, the first shift range will be “5” (fifth range), “\
4”
(fourth range) or “3” (third range) because the suitable shift
range is selected depending on the driving condition.
If you drive in the “S” position: Shift the selector lever
down to the “–” position to select “3” (third range).

STARTING AND DRIVING
361

Shift into the “2” (second range) position. The transmission
will downshift to second gear when the vehicle speed is or
becomes lower than the speed listed below and more
powerful engine braking than that of the “3” (third range)
position will be enabled.
GS430 99 km/h (62 mph)
GS300 (2WD) 93 km/h (58 mph)
GS300 (4WD) 89 km/h (55 mph)
If you drive in the “D” position: Shift the selector lever to
the “S” position and shift the lever down to the “–” posi\
tion
three times 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).
 Shift into the “1” (first range) position. The transmission will
downshift to first gear when the vehicle speed is or becomes
lower than the speed listed below and maximum engine
braking will be enabled.
GS430 37 km/h (23 mph)
GS300 (2WD) 38 km/h (23 mph)
GS300 (4WD) 36 km/h (22 mph)
If you drive in the “D” position: Shift the selector lever to
the “S” position and shift the lever down to the “–” posi\
tion
four 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).
CAUTION
Be careful when downshifting on a slippery surface.
The abrupt change in engine speed could cause the
vehicle to skid or spin.

STARTING AND DRIVING
362
(d) Backing up
G31028
 1Brake pedal 2“R” (Reverse) position
1. Bring the vehicle to a complete stop.
2. With the brake pedal held down with your foot, shift the
selector lever to the “R” position.
NOTICE
Never shift into reverse while the vehicle is moving.
When the selector lever is shifted into the “R” position, the
outside rear view mirrors automatically down to help backing
up. For details, see “Power rear view mirror control” on page
206.
Vehicles with rear view monitor system: When the selector
lever is shifted into the “R” position with the engine switch in
“IG−ON” mode, rear view monitor system will activate. For
instructions, see “Rear view monitor system” on page 388.

STARTING AND DRIVING
363
(e) Parking
G31029
 1Parking brake pedal 2Brake pedal
3“P” (Park) position
1. Bring the vehicle to a complete stop.
2. Depress the parking brake pedal fully to securely apply the
parking brake.
3. With the brake pedal held down with your foot, shift the
selector lever to the “P” position.
CAUTION
Never attempt to move the selector lever into “P” under
any circumstances while the vehicle is moving. Serious
mechanical damage and loss of vehicle control may
result.
(f) Good driving practice
If the transmission repeatedly shifts up and down between
fourth and overdrive gears when climbing a gentle slope, shift
the selector lever to the “4” position. Be sure to shift the
selector lever to the “D” position after climbing the slope.
CAUTION
Always keep your foot on the brake pedal while stopped
with the engine running. This prevents the vehicle from
creeping.
NOTICE
Always use the brake pedal or the parking brake to hold
the vehicle on an upgrade. Do not attempt to hold the
vehicle using the accelerator pedal, as this can cause
the transmission to overheat.

STARTING AND DRIVING
364
(g) If you cannot shift the selector lever
If you cannot shift the selector lever even though the brake
pedal is depressed, use the shift lock override button. For
instructions, see “If you cannot shift automatic transmission
selector lever” on page 489.
ELECTRONIC THROTTLECONTROL SYSTEM
The electronic throttle control system always maintains
appropriate engine output in relation to the accelerator
opening in all driving conditions.
G31023
 1Power position 2Normal position
3Snow position
The electronic throttle control system has 3 modes:
normal, power and snow modes.
Normal mode: For ordinary driving, Lexus recommends that
you use this mode to improve fuel economy.
Power mode: For more powerful acceleration and sporty
driving.