steering Lexus GS250 2012 Repair Manual

3234-5. Using the driving support
4
Driving
GS350/250_EE (OM30C36E)
Guide lines are not dis-
playedThe trunk lid is open.
Close the trunk lid.
If this does not resolve
the symptom, have the
vehicle inspected by
any authorized Lexus
dealer or repairer, or
another duly qualified
and equipped profes-
sional.
“System is initializ-
ing.” is displayed
• The battery has been
reinstalled.
• The steering wheel
has been moved
while the battery was
being reinstalled.
• Battery power is low.
• The steering sensor
has been reinstalled.
• There is a malfunc-
tion in the signals
being output by the
steering sensor.
Stop the vehicle, and
turn the steering wheel
as far as it will go to
the left and right.
If this does not resolve
the symptom, have the
vehicle inspected by
any authorized Lexus
dealer or repairer, or
another duly qualified
and equipped profes-
sional.
• On the system initial-
ization screen, select
the “?” button to dis-
play the operating
procedure.
SymptomLikely causeSolution

3244-5. Using the driving support
GS350/250_EE (OM30C36E)
CAUTION
When using the Lexus parking assist monitor system
When backing up, be sure to check visually behind and all around the vehi-
cle before proceeding.
Observe the following precautions to avoid an accident that could result in
death or serious injuries.
The parking assist monitor is a supplemental device intended to assist the
driver when backing up. Never depend on the parking assist monitor
entirely when backing up. Always make sure your intended path is clear.
Use caution, just as you would when backing up any vehicle.
Never back up while looking only at the screen.
The image shown on the screen may differ from the actual state, and you
could collide with another vehicle or obstacles if backing up looking only
at the screen, possibly causing an accident. When backing up, be sure to
check in front of and behind the vehicle, both directly and with mirrors.
Be sure to back up slowly, depressing the brake pedal to control vehicle
speed.
If you seem likely to hit nearby vehicles, obstacles, people or mount the
shoulder, depress the brake pedal to stop the vehicle, then disable the
assist system by select on the screen to cancel the system.
The instructions given are only guidelines.
When and how much to turn the steering wheel will vary according to
traffic conditions, road surface conditions, vehicle condition, etc. when
parking. It is necessary to be fully aware of this before using the parking
assist system.
When parking, be sure to check that the parking space will accommodate
your vehicle before maneuvering into it.
Do not use system in the following cases:
• On icy or slick road surfaces, or in snow
• When using tire chains or emergency tires
• When the trunk lid is not closed completely
• On roads that are not flat or straight, such as curves or slopes.

3254-5. Using the driving support
4
Driving
GS350/250_EE (OM30C36E)
CAUTION
In low temperatures, the screen may darken or the image may become
faint. The image could distort when the vehicle is moving, or you may
become unable to see the image on the screen. Be sure to check direct
visually and with mirror all around the vehicle before proceeding.
If the tire sizes are changed, the position of the guide lines displayed on
the screen may change.
The camera uses a special lens. The distances between objects and pedes-
trians that appear in the image displayed on the screen will differ from the
actual distances. (P. 316)
When using the perpendicular parking assist screen
The position of the guide lines displayed on the screen may change in
accordance with the number of passengers, the amount of cargo etc. Be
sure to check behind and all around the vehicle direct visually and with
mirror before proceeding.
Estimated course line display mode: If the steering wheel is straight and
the vehicle width extension guide lines and the estimated course lines are
not in alignment, have the vehicle inspected by any authorized Lexus
dealer or repairer, or another duly qualified and equipped professional.
The vehicle width extension guide lines are wider than the actual width of
the vehicle. When backing up, be sure to check behind and all around the
vehicle direct visually and with mirror before proceeding.
When using the parallel parking assist screen
Do not use the system if the display is incorrect due to an uneven (curvy/
hilly) road or a non-straight road.
Make sure to operate the steering wheel only when the vehicle is stopped.
Be sure to check that there are no obstacles inside the blue outline.
If there are any obstacles inside the blue outline, do not use the parallel
parking assist.
When positioning the blue outline over the parking space, be sure to posi-
tion it so that the extended blue line may not cross the tire of the vehicle
parked in front of the empty space.

3294-5. Using the driving support
4
Driving
GS350/250_EE (OM30C36E)Sport mode
Improves acceleration response by controlling the transmission
and steering. Suitable for when precise handling is desirable, for
example when driving on mountain roads.
When the driving mode select switch is turned right, the “SPORT” indica-
tor comes on in the instrument cluster.
Also, on vehicles equipped with a
12.3-inch display, the driving
mode is also automatically dis-
played on the “Side Display”.
(P. 370)
3

331
4 4-5. Using the driving support
Driving
GS350/250_EE (OM30C36E)Sport mode
• SPORT S mode
Improves acceleration response by controlling the transmis-
sion. Suitable for when precise handling is desirable, for
example when driving on mountain roads.
When the driving mode select switch is turned right while a made other
than SPORT S mode is selected, the “SPORT S” indicator comes on in
the instrument cluster.
Also, on vehicles equipped with
a 12.3-inch display, the driving
mode is also automatically dis-
played on the “Side Display”.
(P. 370)
• SPORT S+ mode
Improves steering performance and driving stability by simul-
taneously controlling the steering and suspension in addition
to the transmission. Suitable for sporty driving.
When the driving mode select switch is turned right while SPORT S
mode is selected, the “SPORT S+” indicator comes on in the instrument
cluster.
Also, on vehicles equipped with
a 12.3-inch display, the driving
mode is also automatically dis-
played on the “Side Display”.
(P. 370)
3

3334-5. Using the driving support
4
Driving
GS350/250_EE (OM30C36E)
Driving assist systems
ABS (Anti-lock Brake System)
Helps to prevent wheel lock when the brakes are applied sud-
denly, or if the brakes are applied while driving on a slippery
road surface
Brake assist
Generates an increased level of braking force after the brake
pedal is depressed when the system detects a panic stop situation
VSC (Vehicle Stability Control)
Helps the driver to control skidding when swerving suddenly or
turning on slippery road surfaces
VSC+ (Vehicle Stability Control+)
Provides cooperative control of the ABS, TRC, VSC and EPS.
Helps to maintain directional stability when swerving on slippery
road surfaces by controlling steering performance.
TRC (Traction Control)
Helps to maintain drive power and prevent the drive wheels from
spinning when starting the vehicle or accelerating on slippery
roads
Hill-start assist control
P. 341
To help enhance driving safety and performance, the following
systems operate automatically in response to various driving situa-
tions. Be aware, however, that these systems are supplementary
and should not be relied upon too heavily when operating the vehi-
cle.

3344-5. Using the driving support
GS350/250_EE (OM30C36E)
EPS (Electric Power Steering)
Employs an electric motor to reduce the amount of effort needed
to turn the steering wheel
AVS (Adaptive Variable Suspension system) (if equipped)
By independently controlling the damping force of the shock
absorbers for each of the 4 wheels according to the road and driv-
ing conditions, this system combines riding comfort with supe-
rior steering stability, and ensures good vehicle posture. (P.
328)
VDIM (Vehicle Dynamics Integrated Management)
Provides integrated control of the ABS, brake assist, TRC, VSC,
hill-start assist control and EPS systems
Helps to maintain vehicle stability when swerving on slippery
road surfaces by controlling the brakes, engine output, steering
assist, and steering ratio
PCS (Pre-Crash Safety system) (if equipped)
P. 343
Emergency brake signal
When the brakes are applied suddenly, the stop lights automati-
cally flash to alert the vehicle behind.

3374-5. Using the driving support
4
Driving
GS350/250_EE (OM30C36E)
When the message is displayed on the multi-information display showing that
TRC has been disabled even if the VSC OFF switch has not been pressed
TRC cannot be operated. Contact any authorized Lexus dealer or repairer, or
another duly qualified and equipped professional.
Sounds and vibrations caused by the ABS, brake assist, VSC and TRC sys-
tems
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
operating. 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.
EPS operation sound
When the steering wheel is operated, a motor sound (whirring sound) may be
heard. This does not indicate a malfunction.
Reactivation of the TRC/VSC systems
Even after the TRC/VSC systems have been turned off, turning the engine
off and then on again will automatically reactivate the TRC/VSC systems.

3384-5. Using the driving support
GS350/250_EE (OM30C36E)
Reactivation of the TRC system linked to vehicle speed
When only the TRC system is turned off, the TRC system will turn on when
vehicle speed increases. However, when both TRC and VSC systems are
turned off, the systems will not turn on even when vehicle speed increases.
Reduced effectiveness of the EPS system
The effectiveness of the EPS system 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 engine
off. The effectiveness will improve after a short while.
*: If the LKA (Lane-Keeping Assist) system cannot operate in this case, a
warning message will be shown on the multi-information display.
Operating conditions of emergency brake signal
When the following three conditions are met, the emergency brake signal
will operate:
The emergency flashers are off.
Actual vehicle speed is over 55 km/h (35 mph).
The brake pedal is depressed in a manner that cause the system to judge
from the vehicle deceleration that this is a sudden braking operation.
Automatic system cancelation of emergency brake signal
The emergency brake signal will turn off in any of the following situations:
The emergency flashers are turned on.
The brake pedal is released.
The system judges from the vehicle deceleration that is not a sudden brak-
ing operation.

3474-5. Using the driving support
4
Driving
GS350/250_EE (OM30C36E)
Pre-crash alert braking:
• The system determines that the driver is not facing forward, or that the
driver’s eyes are closed.
• Vehicle speed is greater than about 40 km/h (25 mph).
• The speed at which your vehicle is approaching the vehicle running
ahead of you is greater than about 40 km/h (25 mph).
• The steering is not being turned.
Conditions that may trigger the system even if there is no danger of a collision
When there is an object by the roadside at the entrance to a curve
When passing an oncoming vehicle on a curve
When driving over a narrow iron bridge
When there is a metal object on the road surface
When driving on an uneven road surface
When passing an oncoming vehicle on a left-turn (left-hand drive vehicles)
or right-turn (right-hand drive vehicles)
When your vehicle rapidly closes on the vehicle in front
When a grade separation/interchange, sign, billboard, or other structure
appears to be directly in the vehicle’s line of travel
When climbing a steep hill causes an overhead billboard or other metallic
structure to appear directly in the vehicle’s line of travel
When the system is activated in the situations described above, there is also a
possibility that the seat belts will retract quickly and the brakes will be
applied with a force greater than normal. When the seat belt is locked in the
retracted position, stop the vehicle in a safe place, release the seat belt and
refasten it.
Obstacles not detected
The sensor cannot detect plastic obstacles such as traffic cones. There may
also be occasions when the sensor cannot detect pedestrians, animals, bicy-
cles, motorcycles, trees, or snowdrifts.