engine Lexus GX470 2008 Workshop Manual

160
2-4. Using other driving systems
When the VSC/TRAC/hill-start assist control systems are operating
If the vehicle is in danger of slip-
ping, rolling backwards when
starting on an incline, or if the rear
wheels spin, the slip indicator light
flashes to indicate that the VSC/
TRAC/hill-start assist control sys-
tems have been engaged.
A buzzer (intermittent) sounds to
indicate that VSC is operating.
The stop lights and high mounted
stoplight turn on when the hill-start
assist control system is operating.
The slip indicator light flashes as
well when ABS is operating.
■Sounds and vibrations caused by the ABS, brake assist, VSC, TRAC and hill-start
assist control systems
●A sound may be heard from the engine compartment when the engine is
started or just after the vehicle begins to move. This sound does not indicate that
a malfunction has occurred in any of these systems.
●Any of the following conditions may occur when the above systems are operat-
ing. None of these indicates that a malfunction has occurred.
• Vibrations may be felt through the vehicle body and steering.
• A motor sound may be heard after the vehicle comes to a stop.
• The brake pedal may pulsate slightly after the ABS is activated.
• The brake pedal may move down slightly after the ABS is activated.
■Hill-start assist control is operational when
●The shift lever is in any of the positions “D”, “4”, “3”, “2” or “L”.
●The brake pedal is not depressed.

166
2-5. Driving information
CAUTION
■Off-road driving precautions
Always observe the following precautions to minimize the risk of serious personal
injury or damage to your vehicle:
●Drive carefully when off the road. Do not take unnecessary risks by driving in
dangerous places.
●Do not grip the steering wheel spokes when driving off-road. A bad bump could
jerk the wheel and injure your hands. Keep both hands and especially your
thumbs on the outside of the rim.
●Always check your brakes for effectiveness immediately after driving in sand,
mud, water or snow.
●After driving through tall grass, mud, rock, sand, rivers, etc., check that there is no
grass, bush, paper, rags, stone, sand, etc. adhering or trapped on the underbody.
Clear off any such matter from the underbody. If the vehicle is used with these
materials trapped or adhering to the underbody, a breakdown or fire could occur.
●When driving off-road or in rugged terrain, do not drive at excessive speeds,
jump, make sharp turns, strike objects, etc. This may cause loss of control or vehi-
cle rollover causing death or serious injury. You are also risking expensive dam-
age to your vehicle’s suspension and chassis.
NOTICE
■To prevent the water damage
Take all necessary safety measures to ensure that water damage to the engine or
other components does not occur.
●Water entering the engine air intake will cause severe engine damage.
●Water entering the automatic transmission will cause deterioration in shift quality,
locking up of your transmission accompanied by vibration, and ultimately dam-
age.
●Water can wash the grease from wheel bearings, causing rusting and premature
failure, and may also enter the differentials, transmission and transfer case, reduc-
ing the gear oil’s lubricating qualities.

176
2-5. Driving information
Winter driving tips
Carry out the necessary preparations and inspections before driving the
vehicle in winter. Always drive the vehicle in a manner appropriate to the
prevailing weather conditions.
■Pre-winter preparations
●Use fluids that are appropriate to the prevailing outside tempera-
tures.
• Engine oil
• Engine coolant
• Washer fluid
● Have a service technician inspect the level and specific gravity of
battery electrolyte.
● Have the vehicle fitted with four snow tires or purchase a set of
tire chains for the rear tires.
Ensure that all tires are the same size and brand, and that chains match
the size of the tires.
■ Before driving the vehicle
Perform the following according to the driving conditions.
●Do not try to forcibly open a window or move a wiper that is fro-
zen. Pour warm water over the frozen area to melt the ice. Wipe
away the water immediately to prevent it from freezing.
● To ensure proper operation of the climate control system fan,
remove any snow that has accumulated on the air inlet vents in
front of the windshield.
● Remove any ice that has accumulated on the vehicle chassis.
● Periodically check for and remove any excess ice or snow that
may have accumulated in the wheel well or on the brakes.

179
2-5. Driving information
2
When driving
NOTICE
■Repairing or replacing snow tires
Request repairs of and obtain replacement snow tires from Lexus dealer.
This is because the removal and attachment of snow tires affects the operation of
the tire pressure warning valves and transmitters.
■When jacking up or installing tire chains
Be sure to turn off the rear height control air suspension and stop the engine.
Otherwise, the vehicle height may change because of the automatic leveling func-
tion, resulting in an accident.
■Fitting tire chains
The tire pressure warning valves and transmitters may not function correctly when
tire chains are fitted.

183
2-5. Driving information
2
When driving
Connecting trailer lightsUse the wire harness stored in the rear end underbody.
■When connecting and disconnecting a trailer Connecting
Set the rear height control air suspension to “LO” mode.
Turn off the engine switch or the rear height control air suspension.
Connect the trailer.
Turn on the switch that was turned off on STEP 2.
Set the rear height control air suspension to “N” mode.
Disconnecting
Set the rear height control air suspension to “LO” mode.
Turn off the engine switch or the rear height control air suspension.
Set the supporting leg of the trailer on the ground and raise the hitch by
4 in. (100 mm).
Turn on the switch that was turned off on STEP 2.
Wait until vehicle height is stabilized.
Make sure the hitch is disconnected. If the hitch does not disconnect, raise
the hitch higher and repeat steps 2 through 5.
Move the vehicle forward in the “LO” mode where the hitch does not
touch anything in the “N” mode.
Set the rear height control air suspension in the “N” mode.
STEP1STEP1
STEP2STEP2
STEP1STEP3STEP3
STEP1STEP4STEP4
STEP1STEP5STEP5STEP5
STEP1STEP1
STEP2STEP2
STEP1STEP3STEP3
STEP1STEP4STEP4
STEP1STEP5STEP5STEP5
STEP1STEP5STEP6STEP6STEP6
STEP1STEP5STEP6STEP7STEP7
STEP1STEP5STEP6STEP8STEP8

184
2-5. Driving information
■Before towing
Check that the following conditions are met:
●The vehicle’s tires are properly inflated. (→P. 4 1 9 )
●Trailer tires are inflated according to the trailer manufacturer’s recommenda-
tion.
●All trailer lights work.
●All lights work each time you connect them.
●The trailer ball is set up at the proper height for the coupler on the trailer.
●The vehicle remains level when a loaded or unloaded trailer is hitched. Do not
drive if the vehicle is not level, and check for improper tongue load, overloading,
worn suspension, or other possible causes.
●The trailer cargo is securely loaded.
●The rear view mirrors conform to all applicable federal, state/provincial or local
regulations. If they do not, install rear view mirrors appropriate for towing pur-
poses.
■Break-in schedule
Lexus recommends that you do not use a new vehicle or a vehicle with any new
power train components (engine, transmission, differential, wheel bearings, etc.) to
tow a trailer for the first 500 miles (800 km) of driving.
■Maintenance
●If you tow a trailer, your vehicle will require more frequent maintenance due to
the additional load. (See “Warranty and Services Guide/Owner’s Manual Sup-
plement/Scheduled Maintenance”.)
●Retighten the fixing bolts of the towing ball and bracket after approximately
600 miles (1000 km) of trailer towing.

188
2-5. Driving information
●Note that when making a turn, the trailer wheels will be closer than the
vehicle wheels to the inside of the turn. Compensate by making a
larger than normal turning radius.
● Crosswinds and rough roads will adversely affect handling of your
vehicle and trailer, causing sway. Periodically check the rear to prepare
for being passed by large trucks or buses, which may cause your vehi-
cle and trailer to sway. If swaying occurs, firmly grip the steering wheel,
reduce speed immediately but gradually, and steer straight ahead.
Never increase speed. If you make no extreme correction with the
steering or brakes, your vehicle and trailer will stabilize.
● Take care when passing other vehicles. Passing requires considerable
distance. After passing a vehicle, do not forget the length of your
trailer, and be sure you have plenty of room before changing lanes.
● In order to maintain efficient engine braking and electrical charging
performance, do not use overdrive. Transmission shift range position
must be in “4”.
● Due to the added load of the trailer, your vehicle’s engine may overheat
on hot days (at temperatures over 85°F [30°C] when driving up a
long or steep grade. If the engine coolant temperature gauge indicates
overheating, immediately turn off the air conditioning (if in use), pull
your vehicle off the road and stop in a safe spot. (
→P. 4 0 8 )

189
2-5. Driving information
2
When driving
●Always place wheel blocks under both the vehicle and the trailer
wheels when parking. Apply the parking brake firmly, and put the
transmission in “P”. Avoid parking on a slope, but if unavoidable, do so
only after performing the following:
Apply the brakes and keep them applied.
Have someone place wheel blocks under both the vehicle and
trailer wheels.
When the wheel blocks are in place, release the brakes slowly
until the blocks absorb the load.
Apply the parking brake firmly.
Shift into “P” and turn off the engine.
● When restarting after parking on a slope:
With the transmission in the “P” position, start the engine. Be sure
to keep the brake pedal pressed.
Shift into “3”, “2”, “L”, or “R” position (if reversing).
Release the parking brake and brake pedal, and slowly pull or
back away from the wheel blocks. Stop and apply the brakes.
Have someone retrieve the blocks.
CAUTION
■To avoid an accident
●Do not exceed 45 mph (72 km/h) or the posted towing speed limit, whichever is
lower. A instability (swaying) of the towing vehicle-trailer combination increases
as speed increases, exceeding 45 mph (72 km/h) may cause loss of control.
●Slow down and downshift before descending steep or long downhill grades. Do
not make sudden downshifts.
●Avoid holding the brake pedal down too long or applying the brakes too fre-
quently.
This could cause the brakes to overheat and result in reduced braking efficiency.
STEP1STEP1
STEP2STEP2
STEP1STEP3STEP3
STEP1STEP4STEP4
STEP1STEP5STEP5STEP5
STEP1STEP1
STEP2STEP2
STEP1STEP3STEP3
STEP1STEP4STEP4

197
3-1. Using the air conditioning system and defogger
3
Interior features
CAUTION
■To prevent the windshield from fogging up
Do not use during cool air operation in extremely humid weather. The differ-
ence between the temperature of the outside air and that of the windshield can
cause the outer surface of the windshield to fog up, blocking your vision.
NOTICE
■To prevent battery discharge
Do not leave the automatic air conditioning system on longer than necessary when
the engine is stopped.

198
3-1. Using the air conditioning system and defogger
Rear cooler system
NOTICE
■To prevent battery discharge
Do not leave the rear cooler on longer than necessary when the engine is off.
Rear cooler vents
Fan speed control button
Push either side to adjust the fan speed.
“AUTO” mode: Fan speed is automatically adjusted. Can only be set
if the front air conditioning fan speed is set to “AUTO”.
“REAR COOL” button
Turns the rear cooler on and off.
Does not operate if the front air conditioning is off.
“TEMP” (temperature control) button
Push either side to adjust the temperature.
The rear cooler temperature can be adjusted to within ±10°F
(± 5°C) of the front air conditioning temperature.