Driver assistance systems

The driver assistance systems chapter for the Lexus GS (fourth generation) gives a comprehensive overview of technologies such as ABS, VSC, TRC and Hill-start Assist Control. All of these systems help increase safety and driving stability under a wide range of conditions. Particular attention is given to the conditions for correct use, warnings, and how the systems work together. This gives the driver valuable information to use the systems responsibly.

The following systems operate automatically in response to various driving situations to help increase driving safety and performance. Please keep in mind that these are supplementary systems, and you should not rely on them too heavily while driving.

ABS (Anti-lock Braking System)

Helps prevent the wheels from locking when the brakes are applied suddenly or on slippery road surfaces.

Brake Assist

Generates higher braking force after the brake pedal is depressed when the system detects an emergency braking situation.

VSC (Vehicle Stability Control)

Helps the driver maintain control of the vehicle and prevent skidding during sudden evasive maneuvers or sharp turns on slippery road surfaces.

VSC+ (Vehicle Stability Control VSC+)

Integrates the control of ABS, TRC, VSC and EPS. Helps maintain directional stability when the vehicle begins to slide on slippery roads by controlling steering response.

TRC (Traction Control)

Helps maintain drive power and prevents the drive wheels from spinning when starting off or accelerating on slippery road surfaces.

Hill-Start Assist Control

Prevents the vehicle from rolling backward when starting off on an incline.

EPS (Electric Power Steering)

Uses an electric motor to reduce the effort required to turn the steering wheel.

AVS (Adaptive Variable Suspension) (if equipped)

This system independently controls the damping force of the shock absorbers at each of the 4 wheels according to road and driving conditions. This provides a comfortable ride, excellent steering stability and good vehicle handling. When the "SPORT S+" mode is selected with the drive mode select switch, the damping force is tuned for sporty driving.

VDIM (Vehicle Dynamics Integrated Management)

Integrates the control of ABS, Brake Assist, TRC, VSC, Hill-Start Assist Control and EPS.

Helps maintain vehicle stability during evasive maneuvers on slippery roads by controlling the brakes, engine output, steering assist and steering ratio.

Emergency brake signal

When the brakes are applied suddenly, the brake lights automatically flash to warn the vehicle behind.

When the TRC and VSC systems are operating

The slip indicator light flashes while the TRC and VSC systems are operating.

Turning off the TRC system

If the vehicle becomes stuck in mud, dirt or snow, the TRC system can reduce the drive force transmitted from the engine to the wheels.

If you turn off the system by pressing, you may be able to free the vehicle more easily by rocking it back and forth.

GS350/GS200t

GS F

To turn off the TRC system, briefly press.

GS350/GS200t: The message "TRC OFF" is shown on the multi-information display.

GS F: The "TRC OFF" indicator light comes on.

Pressagain to turn the system back on.

■ Turning off the TRC and VSC systems

GS350/GS200t

Press and holdPress and hold while the vehicle is stationary for more than 3 seconds to turn off the TRC and VSC systems.

The VSC OFF indicator light comes on and the message "TRC OFF" is shown on the multi-information display.* Pressagain to turn the systems back on.

GS F

Press and holdfor more than 3 seconds to turn off the TRC and VSC systems.

The "TRC OFF" indicator light and the VSC OFF indicator light then come on.* Pressagain to turn the systems back on.

*: On vehicles with the Pre-Collision System (PCS), the Pre-Collision Brake Assist and the Pre-Collision Braking function are also deactivated. The Pre-Collision System warning light comes on and a message is shown on the multi-information display.

■ Expert mode (GS F)

When you select expert mode, you can drive more sportily than in other drive modes.

In expert mode, the TRC and VSC systems are deactivated; however, depending on vehicle behavior, the engine and brakes may still be controlled.

To select expert mode, presswhile "SPORT S" mode is active.

The "EXPERT" indicator light then comes on together with the "TRC OFF" indicator light and the VSC OFF indicator light.

To turn off expert mode, pressor use the drive mode select switch to change from "SPORT S+" mode to another mode.

■If the multi-information display shows a message that TRC has been turned off even though the switch has not been pressed (GS350/GS200t)

Traction Control (TRC) and Hill-Start Assist Control cannot be used.

Contact a Lexus dealer or authorized repairer, or another qualified and properly equipped repair shop.

■If the "TRC OFF" indicator light comes on even thoughhas not been pressed (GS F)

Traction Control (TRC) and Hill-Start Assist Control cannot be used.

Contact a Lexus dealer or authorized repairer, or another qualified and properly equipped repair shop.

■ Noises and vibrations caused by ABS, Brake Assist, VSC, Hill-Start Assist Control and TRC

• When the engine is started or immediately after starting off, a noise may be heard from the engine compartment when the brake pedal is pressed repeatedly. This noise does not indicate a malfunction of any of these systems.
• The following situations may occur while the above systems are operating.

  None of these indicate a malfunction.

Vibrations may be felt through the body and steering. After the vehicle stops, an operating noise may be heard. The brake pedal may pulsate slightly when the ABS is activated. The brake pedal may move slightly downward when the ABS is activated.

■ EPS operating noise

An operating noise (humming) may be heard when the steering wheel is turned. This does not indicate a malfunction.

■ Automatic reactivation of the TRC and VSC systems

After the TRC and VSC systems have been turned off, these systems are automatically reactivated in the following situations:

• When the engine switch is turned off
• If only the TRC system was turned off, it turns back on when the vehicle speed increases.

  If both the TRC and VSC systems were turned off, they are not automatically reactivated when the vehicle speed increases.

■ Reduced EPS assist

To protect the system from overheating, the EPS system's assist is reduced if frequent steering inputs are made over an extended period. As a result, the steering wheel may feel heavy. In this case, avoid excessive steering inputs, or stop the vehicle and turn off the engine. The EPS system should return to normal operation within 10 minutes.

■ Operating conditions for Hill-start Assist Control

Hill-start Assist Control is activated when all of the following four conditions are met:

• The shift lever is in a position other than "N" or "P" (when starting forward or in reverse on a slope).
• The vehicle is stopped.
• The accelerator pedal is not depressed.
• The parking brake is not applied.

■ Automatic deactivation of Hill-start Assist Control

Hill-start Assist Control is deactivated in the following situations:

• The shift lever is moved to "N" or "P".
• The accelerator pedal is depressed.
• The parking brake is applied.
• Approximately 2 seconds have passed since the brake pedal was released.

■ Operating conditions for the Emergency Stop Signal

The Emergency Stop Signal is activated when all of the following three conditions are met:

• The hazard warning lights are off.
• The vehicle speed is more than 55 km/h.
• The brake pedal is depressed in a manner that, based on the vehicle deceleration, the system determines to be an emergency braking situation.

■ Automatic deactivation of the Emergency Stop Signal

The Emergency Stop Signal is deactivated in the following situations:

• The hazard warning lights are turned on.
• The brake pedal is released.
• Based on the vehicle deceleration, the system determines that emergency braking is no longer taking place.

WARNING

■ ABS does not operate efficiently in the following cases

• The limits of tire grip have been exceeded (for example, excessively worn tires on a snow-covered road).
• Hydroplaning occurs at high speed on wet or slippery roads.

■ Stopping distance with ABS operating may be longer than stopping distance under normal conditions

ABS is not designed to shorten the vehicle's stopping distance. Always maintain a sufficient distance from the vehicle ahead, especially in the following situations:

• When driving on dirt, gravel or snow-covered roads
• When using snow chains
• When driving over bumps
• On roads with potholes or uneven surfaces

■ TRC may not operate efficiently in the following cases

On slippery roads, it may not be possible to maintain directional control and vehicle performance, even with TRC activated.

Drive carefully in conditions where stability and performance may be lost.

■ Hill-start Assist Control does not operate efficiently in the following cases

• Do not rely too heavily on Hill-start Assist Control. Hill-start Assist Control may not operate efficiently on steep slopes or icy roads.
• Unlike the parking brake, Hill-start Assist Control is not intended to hold the vehicle in place for an extended period. Do not attempt to hold the vehicle on a slope using Hill-start Assist Control, as this may lead to an accident.

■ When VSC is activated

The slip indicator light is flashing. Always drive carefully. Risky driving may lead to accidents. Be especially careful when the light is flashing.

■ When TRC and VSC are deactivated

Use extra caution and drive at a speed appropriate to road conditions. Turn off TRC and VSC only when absolutely necessary, as these systems help maintain vehicle stability and traction.

WARNING

■ Precautions for Expert Mode (GS F)

• Do not use this mode on public roads.
• Use this mode only when you can ensure that road conditions are suitable and the surroundings are safe.
• Proper use of Expert Mode requires professional-level driving skills. When using Expert Mode, always check road conditions and surroundings and drive more carefully than usual.

■ Tire replacement

Make sure that all tires match the specifications for size, brand, tread pattern and total load capacity. Also make sure that the tires are inflated to the recommended tire pressure.

ABS, TRC and VSC will not function properly if tires of different types are fitted to the vehicle.

For more information on replacing tires or wheels, contact a Lexus dealer or authorized repairer, or another qualified repair facility with the appropriate equipment.

■ Handling tires and suspension

Using defective tires or modifying the suspension will impair the driver assist systems and may cause a system malfunction.

The driver assist systems of the Lexus GS 4th generation combine safety and comfort at the highest level. Systems such as ABS, VSC, TRC and Adaptive Variable Suspension (AVS) work together in harmony to assist in critical driving situations. VDIM provides integrated control of all key vehicle dynamics systems.

Thanks to this technology, the Lexus GS GRL1 sports sedan remains controllable at all times, even on difficult road surfaces or during unexpected maneuvers. Safety and performance go hand in hand here.