light Lexus GX470 2008 Using other driving systems / LEXUS 2008 GX470 (OM60D82U) Repair Manual

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2-4. Using other driving systems
■The center differential lock/unlock button can be operated when
●The engine switch is in the “ON” position, and
●The four-wheel drive control lever is in the “H” or “L” position.
■Locking/unlocking the center differential
●When the center differential is locked, VSC is automatically turned off. (The
center differential lock and “VSC OFF” indicator lights come on.)
●If the operation is not completed, the center differential lock indicator blinks. If
the indicator light does not go off when unlocking the center differential, drive
straight ahead while accelerating or decelerating, or drive in reverse.
●If center differential lock system oper ation is not completed within 5 seconds
while the cruise control system is set, cancel the cruise control system.
CAUTION
■While driving
Never move the four-wheel drive control lever if the wheels are slipping. Doing so
may cause an accident resulting in death or serious injury.
NOTICE
■To prevent damage to the center differential
●Unlock the center differential after the wh eels are out of the ditch or off the loose
or bumpy surface.
●Do not push the center differential lock/u nlock button when the vehicle is corner-
ing or when its wheels are spin ning freely off the ground.

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2-4. Using other driving systems
2
When driving
Rear height control air suspension
The rear height control air suspension adjusts the rear vehicle height in
accordance with driving conditions. There are 3 selectable modes, “HI”
(high), “N” (normal), and “LO” (low).
■Height control switch
“▲ ” (Up) switch
“ ▼ ” (Down) switch
“OFF” switch
Push while the vehicle is
stopped. The “OFF” indicator
light will come on, and the vehi-
cle height will be fixed in the
current mode. Push the switch
again to turn the system back
on.

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2-4. Using other driving systems
■Height control indicator lights
Height control mode indica-
tors
Height control “OFF” indica-
tor

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2-4. Using other driving systems
Height control indicator lightsIf you change the vehicle height mode, the indicator lights change as fol-
lows: • The current mode indicator light w ill turn off, and the selected mode
indicator light will begin flashing.
• Once the change in vehicle height is complete, the selected mode indicator light will change fr om flashing to continuously lit.
■Operating conditions
●The engine must be running.
●Vehicle speed must be within the acce ptable range for the selected mode.
■Automatic change in vehicle height
If the vehicle speed exceeds 19 mph (30 km/h) when in the high mode, or 7 mph
(12 km/h) when in the low mode, normal mode is automatically selected.
■Turning off the rear height control air suspension
●The system will remain off until the switch is pushed again, even if the engine
switch is turned off.
●Even if the rear height control air suspen sion is turned off, the system automati-
cally selects the normal mode if the vehicle’s speed exceeds 19 mph (30 km/h).
■Automatic leveling function
The vehicle is adjusted to a fixed height for each mode, regardless of the number of
occupants and the luggage load.

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2-4. Using other driving systems
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When driving
■If the vehicle height does not change
If the area around the rear suspension is coated with ice, or the undercarriage has
come into contact with the road surface, the rear height control suspension will not
operate. In this case, the indicator lights will change as follows:
●The current mode indicator light will turn off, and the target mode indicator light
will begin flashing.
●The target mode indicator light will turn off, and the original mode indicator light
will be lit once more. (The vehicle height does not change.)
If the rear height control air suspension cannot be operated even after removing
the ice or progressing to a smooth driving surface, turn off and restart the engine.
■ Parking and stopping tips
●If you immediately stop the engine after of f-road driving, or park the vehicle for
a long time, the vehicle height may gradually lower. When parking, make sure
there is nothing under the vehicle that may come in contact with the underbody.
The vehicle will return to the set height when the engine is started.
●The vehicle height may change as the temperature changes when the engine is
stopped. The vehicle will return to the set height when the engine is started.
■When lowering the vehicle
Even if the engine is stopped while the ve hicle height is being lowered, operation
will continue for up to 25 seconds. If any of the side doors or the back door is
opened within this 25 seconds, operatio n will continue for a further 15 seconds.
■ Rear height control failure warning
●If a malfunction occurs in the rear height control air suspension, normal mode is
automatically selected.
The height control “OFF” indicator will blink, and the vehicle height control can-
not be activated until the malfunction is corrected. Have the vehicle checked at
your Lexus dealer as soon as possible.
●If the height control “OFF” indicator li ght does not come on when the engine
switch is turned to the “ON” position, there is a malfunction in the rear height
control air suspension. You can continue normal driving, however have the vehi-
cle checked by your Lexus dealer as soon as possible.

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2-4. Using other driving systems
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When driving
NOTICE
■To avoid damage to the vehicle
●If in the low mode, the vehicle automatically shifts to the normal mode (vehicle
height is raised) when the engine is started. Take care when overhead height is
limited.
●After unloading, the vehicle height may be slightly higher than normal. Take care
when overhead height is limited.
●Before lowering the vehicle height, check that no-one is under the vehicle and
the area is free of obstructions. Also check that the underbody of the vehicle will
not touch the ground.
●Do not select the low mode when drivin g on bumpy roads, as the underbody of
the vehicle may contact the road surface.
■ Avoid rapid changes to the vehicle height when the vehicle is heavily loaded
As the compressor may overheat, causing the vehicle height adjustment operation
to stop.

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2-4. Using other driving systems
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When driving
DAC (Downhill Assist Control system)
The DAC helps to prevent excessive speed on steep downhill slopes.
The system will operate when the vehicle is traveling under 15 mph
(25 km/h) and the four wheel drive control lever is in the “L” position.
■System operation
Press the “DAC” switch. The
indicator will come on, and the
system will operate.
When the system is in operation,
the slip indicator light will flash,
and the stop lights/high
mounted stop lights will be lit.
■Turning off the system
Press the “DAC” switch while the system is in operation. The indica-
tor will flash as the system gradua lly ceases operation, and will turn
off when the system is fully off.
Press the “DAC” switch while the indicator is flashing to start the
system again.

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2-4. Using other driving systems
When the VSC/TRAC/hill-start assist control systems are operatingIf 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 engi ne 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.

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2-4. Using other driving systems
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When driving
CAUTION
Any of the following conditions may result in an accident which could cause death or
serious injury:
■The ABS does not operate effectively when
●The limits of tire gripping performance have been exceeded.
●The vehicle hydroplanes while driving at high speed on the wet or slick road.
■Stopping distance when the ABS is operating on the wet or slick roads
The ABS is not designed to shorten the ve hicle’s stopping distance. Always main-
tain a safe distance from the vehicle in front of you in the following situations.
●When driving on dirt, gravel or snow-covered roads
●When driving with tire chains
●When driving over bumps in the road
●When driving over roads with potholes or roads with uneven roads
■TRAC may not operate effectively when
Directional control and power may not be ac hievable while driving on slippery road
surfaces, even if the TRAC is operating.
Do not drive the vehicle in conditions where stability and power may be lost.
■The hill-start assist control may not operate effectively when
●On steep inclines.
●On icy surfaces.
■When the VSC is activated
The slip indicator light flashes and a warning buzzer sounds. Always drive carefully.
Reckless driving may cause an accident. Ex ercise particular care when the indica-
tor light flashes and a buzzer sounds.

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2-5. Driving information
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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.
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