2009 Lexus GS450h Owner's Manual

216
2-4. Using other driving systems
GS_HV_U (OM30B44U)
April 27, 2009 10:09 am
To disable TRAC and/or Enhanced VSCIf the vehicle gets stuck in fresh snow or mud, TRAC and Enhanced VSC
may reduce power from the engine to the wheels. You may need to turn
the system off to enable you to rock the vehicle in order to free it.
■ Turning off TRAC only
Quickly push and release the but-
ton to turn off TRAC.
The message “TRAC OFF”
appears on the multi-information
display.
Push the button again to turn the
system back on.
GS450h_HV_U.book Page 216 Monday, April 27, 2009 10:10 AM

217
2-4. Using other driving systems
2
When driving
GS_HV_U (OM30B44U)
April 27, 2009 10:09 am
■Turning off both TRAC and Enhanced VSC
Push and hold the button for more
than 3 seconds while the vehicle is
stopped to turn off TRAC and
Enhanced VSC.
The slip off indicator light should
come on and the message “TRAC
OFF” appears on the multi-infor-
mation display.
Push the button again to turn the
system back on.
GS450h_HV_U.book Page 217 Monday, April 27, 2009 10:10 AM

218
2-4. Using other driving systems
GS_HV_U (OM30B44U)
April 27, 2009 10:09 am
■Automatic reactivation of TRAC and Enhanced VSC
Turning the “POWER” switch OFF after turning off the TRAC and Enhanced VSC
systems will automatically re-enable them.
■Automatic TRAC reactivation
If only the TRAC system is turned off, the TRAC system will turn on when the vehi-
cle speed increases.
■Automatic TRAC and Enhanced VSC reactivation
If the TRAC and Enhanced VSC systems are turned off, the systems will not turn on
even when the vehicle speed increases.
■Sounds and vibrations caused by the ABS, brake assist, Enhanced VSC, TRAC,
hill-start assist control and VGRS systems
●A sound may be heard from the engine compartment when the hybrid system 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 operating conditions
This system comes into operation under the following conditions after the brake
pedal has been depressed and the vehicle has come to a stop:
●The shift lever is in the “D” or “S”.
●The system has detected that the vehicle is moving backwards.
■EPS operation sound
When the steering wheel operates, a motor sound (whirring sound) may be heard.
This does not indicate a malfunction.
GS450h_HV_U.book Page 218 Monday, April 27, 2009 10:10 AM

219
2-4. Using other driving systems
2
When driving
GS_HV_U (OM30B44U)
April 27, 2009 10:09 am
■Reduced effectiveness of EPS
The effectiveness of EPS is reduced to prevent the system from overheating when
there is frequent steering input over an extended period of time. The steering wheel
may feel heavy as a result. Should this occur, refrain from excessive steering input or
stop the vehicle and turn the hybrid system off. The system should return to normal
about 10 minutes.
■VGRS is disabled in the following situations
●During stopping or the steering wheel has been moved for a long time while
driving at lower speeds.
●After the hybrid system is restarted at less than -22°F (-30°C).
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 a wet or slick road.
■Stopping distance when the ABS is operating will exceed that of normal condi-
tions
The ABS is not designed to shorten the vehicle’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 achievable 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.
GS450h_HV_U.book Page 219 Monday, April 27, 2009 10:10 AM

220
2-4. Using other driving systems
GS_HV_U (OM30B44U)
April 27, 2009 10:09 am
CAUTION
■The hill-start assist control may not operate effectively when
●On steep inclines.
●On icy surfaces.
■When the Enhanced VSC is activated
The slip indicator light flashes and a warning buzzer sounds. Always drive carefully.
Reckless driving may cause an accident. Exercise particular care when the indica-
tor light flashes and a buzzer sounds.
■When TRAC and Enhanced VSC are off
Be especially careful and drive at a speed appropriate to the road conditions. As
these are systems to ensure vehicle stability and driving force, do not turn off TRAC
and Enhanced VSC unless necessary.
■Replacing tires
Make sure that all tires are of the same size, brand, tread pattern and total load
capacity. In addition, make sure that the tires are inflated to the specified tire pres-
sure level.
The ABS and Enhanced VSC will not function correctly if different tires are fitted on
the vehicle.
Contact your Lexus dealer for further information when replacing tires or wheels.
■Handling of tires and suspension
Using tires with any kind of problem or modifying the suspension will affect the driv-
ing assist systems, and may cause the system to malfunction.
GS450h_HV_U.book Page 220 Monday, April 27, 2009 10:10 AM

221
2-4. Using other driving systems
2
When driving
GS_HV_U (OM30B44U)
April 27, 2009 10:09 am
PCS (Pre-Collision System)∗
∗: If equipped
Safety systems such as the brakes and seat belts are automatically
engaged to lessen impact and injuries to occupants as well as vehicle dam-
age when the radar sensor detects an unavoidable frontal collision.
■Pre-collision seat belts (front seats only)
If the pre-collision sensor detects that a collision is unavoidable, the pre-
collision system will retract the seat belt before the collision occurs.
The same will happen if the driver makes an emergency braking or loses
control of the vehicle. ( →P. 7 5 )
■Pre-collision brake assist
Applies greater braking force in relation to how strongly the brake pedal is
depressed.
■AV S
If the system determines that the collision is unavoidable, the operation of
AV S ( →P. 213) helps prevent the vehicle front from going down when
hard brakes are applied.
GS450h_HV_U.book Page 221 Monday, April 27, 2009 10:10 AM

222
2-4. Using other driving systems
GS_HV_U (OM30B44U)
April 27, 2009 10:09 am
Radar sensorDetects vehicles or other obsta-
cles on or near the road ahead and
determines whether a collision is
imminent based on the position,
speed, and heading of the obsta-
cles. Grille cover
Radar sensor
GS450h_HV_U.book Page 222 Monday, April 27, 2009 10:10 AM

223
2-4. Using other driving systems
2
When driving
GS_HV_U (OM30B44U)
April 27, 2009 10:09 am
■Obstacles not detected
The sensor cannot detect plastic obstacles such as pylons. There may also be occa-
sions when the radar sensor cannot detect pedestrians, animals, bicycles, motorcy-
cles, trees, or snowdrifts.
■The pre-collision system is operational when
●Pre-collision seat belts (linked to the radar sensor)
• Vehicle speed is above 3 mph (5 km/h).
• The speed at which your vehicle is approaching the obstacle or oncomingvehicle exceeds 18 mph (30 km/h).
• The front occupants are wearing a seat belt.
●Pre-collision seat belts (linked to brake operation)
• Vehicle speed exceeds 18 mph (30 km/h).
• The system detects sudden braking or skidding.
• The front occupants are wearing a seat belt.
●Pre-collision brake assist
• Vehicle speed is above 18 mph (30 km/h).
• The speed at which your vehicle is approaching the obstacle or oncoming vehicle exceeds 18 mph (30 km/h).
• The brake pedal is depressed.
●AV S
• Vehicle speed is above 3 mph (5 km/h).
• The speed at which your vehicle is approaching the obstacle or oncoming
vehicle exceeds 18 mph (30 km/h).
GS450h_HV_U.book Page 223 Monday, April 27, 2009 10:10 AM