LANE-KEEPING ASSIST SYSTEM

FUNCTION OF MAIN COMPONENTS

Components		Function
Forward Recognition Camera		Captures a view of the road ahead of the vehicle and detects lane markers on the driving lane, and calculates the radius to the center of the lane, lane width, distance from markers and heading angle deviation. Controls the lane departure alert function, steering assist function and vehicle sway warning function. Sends the indicator illumination request signal, multi-information display indication light request signal, and meter buzzer sound request signal to the combination meter assembly. Sends the system condition signal to the headup display. Receives vehicle information and turn signal light operation signals and sends a steering force signal to the power steering ECU assembly. Sends an operation signal to the camera heater.
Camera Heater (Forward Recognition Hood with Heater Sub-assembly)		The camera heater is heated according to signals from the forward recognition camera.
Driving Support ECU Assembly		Calculates the amount of steering assist in accordance with signals from switches and ECUs. Sends the LKA main switch signal to the forward recognition camera. Controls the lane centering function.
Millimeter Wave Radar Sensor Assembly		Radiates millimeter radar waves forward, uses the reflected waves to detect the presence of a vehicle traveling ahead, the vehicle-to-vehicle distance, and the relative speed, and then sends this information to the forward recognition camera.
Combination Meter Assembly		Sends a turn signal command to the forward recognition camera.
Combination Meter Assembly	LKA Indicator	Illuminates or turns off in accordance with signals from the forward recognition camera.
	Multi-information Display	Displays a warning message and white lines to inform or warn the driver of the system condition in accordance with signals from the forward recognition camera.
	Master Warning Light	Illuminates to warn the driver in accordance with signals from the forward recognition camera.
	Meter Buzzer	Sounds to warn the driver in accordance with signals from the forward recognition camera.
ECM		Sends the accelerator pedal opening angle signal to the forward recognition camera.
Skid Control ECU Assembly		Sends a vehicle speed signal from the speed sensor to the forward recognition camera and driving support ECU assembly.
Steering Pad Switch Assembly	LKA Main Switch	Detects the on/off status of the lane keeping assist system and sends a signal to the driving support ECU assembly.
Steering Pad Switch Assembly	Meter Control Switch	Changes the customization settings of the lane keeping assist system.
Yawrate Sensor		Detects the yaw rate and sends a signal to the forward recognition camera.
Steering Sensor		Sends the turning angle of the steering wheel to the forward recognition camera and driving support ECU assembly. Sends a turn signal command to the combination meter assembly.
Headlight Dimmer Switch Assembly		Transmits a turn signal command to the combination meter assembly.
Steering Vibration and Heater ECU		Controls the steering vibration according to signals from the forward recognition camera.
Power Steering ECU Assembly		Controls the power steering motor and performs steering assist based on signals received from the forward recognition camera. Detects steering operations performed by the driver and sends the operations to the forward recognition camera. Cancels steering assist when an abnormal torque request signal is received from the forward recognition camera.
Combination Meter Mirror Assembly*		Displays the system condition in accordance with a signal from the forward recognition camera.
Network Gateway ECU		Relays the signal between the CAN communication buses.
DLC3		The Global TechStream (GTS) can be connected to read the Diagnostic Trouble Codes (DTCs) of malfunctions.

*: Models with headup display

OPERATION CONDITION

Operating Conditions of Lane Keeping Assist System (Lane Departure Alert Function)

Operation	Condition
Operating	The lane keeping assist system (lane departure alert function) is activated when all of the following conditions are met: The LKA main switch is on. (When the LKA main switch is pressed to turn on the lane keeping assist system, the LKA indicator illuminates.) The vehicle speed is approximately 50 km/h (32 mph) or more. Lane markers are detected. No turn signal command is detected. A system malfunction is not detected.
Suspended	The lane keeping assist system (lane departure alert function) is suspended when any one of the following conditions is met: The vehicle speed is less than approximately 50 km/h (32 mph). A turn signal command is detected. No lane markers are detected. Immediately after the lane departure alert is activated. The vehicle crosses halfway or further over a lane marker. Detection of the lane width other than regulated. Detection of the curve radius other than regulated. A malfunction is detected in the lane keeping assist system. The temperature of the forward recognition camera is abnormal.
Canceled/Resume	The lane keeping assist system (lane departure alert function) is stopped when any one of the following conditions is met: The LKA main switch is off. The lane keeping assist system is temporarily stopped. The lane keeping assist system is malfunctioning. The engine switch is turned off. The lane keeping assist system (lane departure alert function) resumes when the following conditions are met: The conditions to start operation listed above are satisfied. The lane keeping assist system condition returns to normal. The engine switch is turned off and on (IG) again to ensure normal operation, after the lane keeping assist system has been stopped by a system malfunction.

Operation

Condition

Operating

The lane keeping assist system (lane departure alert function) is activated when all of the following conditions are met:

The LKA main switch is on. (When the LKA main switch is pressed to turn on the lane keeping assist system, the LKA indicator illuminates.)
The vehicle speed is approximately 50 km/h (32 mph) or more.
Lane markers are detected.
No turn signal command is detected.
A system malfunction is not detected.

Suspended

The lane keeping assist system (lane departure alert function) is suspended when any one of the following conditions is met:

The vehicle speed is less than approximately 50 km/h (32 mph).
A turn signal command is detected.
No lane markers are detected.
Immediately after the lane departure alert is activated.
The vehicle crosses halfway or further over a lane marker.
Detection of the lane width other than regulated.
Detection of the curve radius other than regulated.
A malfunction is detected in the lane keeping assist system.
The temperature of the forward recognition camera is abnormal.

Canceled/Resume

The lane keeping assist system (lane departure alert function) is stopped when any one of the following conditions is met:

The LKA main switch is off.
The lane keeping assist system is temporarily stopped.
The lane keeping assist system is malfunctioning.
The engine switch is turned off.

The lane keeping assist system (lane departure alert function) resumes when the following conditions are met:

The conditions to start operation listed above are satisfied.
The lane keeping assist system condition returns to normal.
The engine switch is turned off and on (IG) again to ensure normal operation, after the lane keeping assist system has been stopped by a system malfunction.

Operating Conditions of Lane Keeping Assist System (Steering Assist Function)

Operation	Condition
Operating	The lane keeping assist system (steering assist function) is activated when all of the following conditions are met: The LKA main switch is on. (When the LKA main switch is pressed to turn on the lane keeping assist system, the LKA indicator illuminates.) The vehicle speed is approximately 50 km/h (32 mph) or more. Lane markers are detected. No turn signal command is detected. A system malfunction is not detected. Steering assist available is selected via operation of the steering pad switch assembly. Deceleration at or above a constant speed is not detected. Steering operations to change the direction of vehicle travel are not performed. Systems related to vehicle safety, such as the VSC and pre-collision system, do not operate. Acceleration via operation of the accelerator pedal is not detected. The hands off steering wheel alert is not displayed.
Suspended	The lane keeping assist system (steering assist function) is suspended when any one of the following conditions is met: The vehicle speed is less than approximately 50 km/h (32 mph). A turn signal command is detected. No lane markers are detected. Immediately after the lane departure control function is activated. The yawrate sensor is malfunctioning. The deceleration sensor or steering sensor is malfunctioning. The vehicle crosses halfway or further over a lane marker. Steering assist generated to change the direction of vehicle travel is detected. Deceleration at or above a constant speed is detected. Systems related to vehicle safety, such as the VSC and pre-collision system, operate. Acceleration via operation of the accelerator pedal is detected. No steering wheel operation detected. Detection of the lane width other than regulated. Detection of the curve radius other than regulated. A malfunction is detected in the lane keeping assist system. The temperature of the forward recognition camera is abnormal.
Canceled/Resume	The lane keeping assist system (steering assist function) is stopped when any one of the following conditions is met: The LKA main switch is off. The lane keeping assist system is malfunctioning. The lane keeping assist system is temporarily stopped. The engine switch is turned off. Steering assist unavailable is selected via operation of the steering pad switch assembly. The lane keeping assist system (steering assist function) resumes when the following conditions are met: The conditions to start operation listed above are satisfied. The lane keeping assist system condition returns to normal. The engine switch is turned off and on (IG) again to ensure normal operation, after the lane keeping assist system has been stopped by a system malfunction. Steering assist available is selected via operation of the steering pad switch assembly.

Operation

Condition

Operating

The lane keeping assist system (steering assist function) is activated when all of the following conditions are met:

The LKA main switch is on. (When the LKA main switch is pressed to turn on the lane keeping assist system, the LKA indicator illuminates.)
The vehicle speed is approximately 50 km/h (32 mph) or more.
Lane markers are detected.
No turn signal command is detected.
A system malfunction is not detected.
Steering assist available is selected via operation of the steering pad switch assembly.
Deceleration at or above a constant speed is not detected.
Steering operations to change the direction of vehicle travel are not performed.
Systems related to vehicle safety, such as the VSC and pre-collision system, do not operate.
Acceleration via operation of the accelerator pedal is not detected.
The hands off steering wheel alert is not displayed.

Suspended

The lane keeping assist system (steering assist function) is suspended when any one of the following conditions is met:

The vehicle speed is less than approximately 50 km/h (32 mph).
A turn signal command is detected.
No lane markers are detected.
Immediately after the lane departure control function is activated.
The yawrate sensor is malfunctioning.
The deceleration sensor or steering sensor is malfunctioning.
The vehicle crosses halfway or further over a lane marker.
Steering assist generated to change the direction of vehicle travel is detected.
Deceleration at or above a constant speed is detected.
Systems related to vehicle safety, such as the VSC and pre-collision system, operate.
Acceleration via operation of the accelerator pedal is detected.
No steering wheel operation detected.
Detection of the lane width other than regulated.
Detection of the curve radius other than regulated.
A malfunction is detected in the lane keeping assist system.
The temperature of the forward recognition camera is abnormal.

Canceled/Resume

The lane keeping assist system (steering assist function) is stopped when any one of the following conditions is met:

The LKA main switch is off.
The lane keeping assist system is malfunctioning.
The lane keeping assist system is temporarily stopped.
The engine switch is turned off.
Steering assist unavailable is selected via operation of the steering pad switch assembly.

The lane keeping assist system (steering assist function) resumes when the following conditions are met:

The conditions to start operation listed above are satisfied.
The lane keeping assist system condition returns to normal.
The engine switch is turned off and on (IG) again to ensure normal operation, after the lane keeping assist system has been stopped by a system malfunction.
Steering assist available is selected via operation of the steering pad switch assembly.

Operating Conditions of Lane Keeping Assist System (Lane Centering Function)

Operation	Condition
Operating	The lane keeping assist system (lane centering function) is activated when all of the following conditions are met: The LKA main switch is on. (When the LKA main switch is pressed to turn on the lane keeping assist system, the LKA indicator illuminates.) Steering assist available is selected via operation of the steering pad switch assembly. Center trace available is selected via operation of the steering pad switch assembly. Lane markers are detected. Dynamic radar cruise control system (vehicle-to-vehicle distance control mode) is operating. The vehicle is driving in a lane with a width of operation condition of each function Lane departure control function is not operating. No turn signal command is detected. A system malfunction is not detected. Deceleration at or above a constant speed is not detected. Steering operations to change the direction of vehicle travel are not performed. Systems related to vehicle safety, such as the VSC and pre-collision system, do not operate. Acceleration via operation of the accelerator pedal is not detected. The hands off steering wheel alert is not displayed.
Suspended	The lane keeping assist system (lane centering function) is suspended when any one of the following conditions is met: Dynamic radar cruise control system (vehicle-to-vehicle distance control mode) do not operate. A turn signal command is detected. One side of lane markers is not detected. The yawrate sensor is malfunctioning. The vehicle crosses halfway or further over a lane marker. Steering operations to change the direction of vehicle travel are performed. Deceleration at or above a constant speed is detected. Systems related to vehicle safety, such as the VSC and pre-collision system, operate. Acceleration via operation of the accelerator pedal is detected. The deceleration sensor or steering sensor is malfunctioning. Detection of the lane width other than regulated. Detection of the curve radius other than regulated. A malfunction is detected in the lane keeping assist system. The temperature of the forward recognition camera is abnormal.
Canceled/Resume	The lane keeping assist system (lane centering function) is stopped when any one of the following conditions is met: The LKA main switch is off. The cruise control main switch is off. The lane keeping assist system is temporarily stopped. The lane keeping assist system is malfunctioning. The engine switch is turned off. Steering assist unavailable is selected via operation of the steering pad switch assembly. Center trace unavailable is selected via operation of the steering pad switch assembly. The lane keeping assist system (lane centering function) resumes when the following conditions are met: The conditions to start operation listed above are satisfied. The lane keeping assist system condition returns to normal. The engine switch is turned off and on (IG) again to ensure normal operation, after the lane keeping assist system has been stopped by a system malfunction. Center trace available is selected via operation of the steering pad switch assembly.

Operation

Condition

Operating

The lane keeping assist system (lane centering function) is activated when all of the following conditions are met:

The LKA main switch is on. (When the LKA main switch is pressed to turn on the lane keeping assist system, the LKA indicator illuminates.)
Steering assist available is selected via operation of the steering pad switch assembly.
Center trace available is selected via operation of the steering pad switch assembly.
Lane markers are detected.
Dynamic radar cruise control system (vehicle-to-vehicle distance control mode) is operating.
The vehicle is driving in a lane with a width of operation condition of each function
Lane departure control function is not operating.
No turn signal command is detected.
A system malfunction is not detected.
Deceleration at or above a constant speed is not detected.
Steering operations to change the direction of vehicle travel are not performed.
Systems related to vehicle safety, such as the VSC and pre-collision system, do not operate.
Acceleration via operation of the accelerator pedal is not detected.
The hands off steering wheel alert is not displayed.

Suspended

The lane keeping assist system (lane centering function) is suspended when any one of the following conditions is met:

Dynamic radar cruise control system (vehicle-to-vehicle distance control mode) do not operate.
A turn signal command is detected.
One side of lane markers is not detected.
The yawrate sensor is malfunctioning.
The vehicle crosses halfway or further over a lane marker.
Steering operations to change the direction of vehicle travel are performed.
Deceleration at or above a constant speed is detected.
Systems related to vehicle safety, such as the VSC and pre-collision system, operate.
Acceleration via operation of the accelerator pedal is detected.
The deceleration sensor or steering sensor is malfunctioning.
Detection of the lane width other than regulated.
Detection of the curve radius other than regulated.
A malfunction is detected in the lane keeping assist system.
The temperature of the forward recognition camera is abnormal.

Canceled/Resume

The lane keeping assist system (lane centering function) is stopped when any one of the following conditions is met:

The LKA main switch is off.
The cruise control main switch is off.
The lane keeping assist system is temporarily stopped.
The lane keeping assist system is malfunctioning.
The engine switch is turned off.
Steering assist unavailable is selected via operation of the steering pad switch assembly.
Center trace unavailable is selected via operation of the steering pad switch assembly.

The lane keeping assist system (lane centering function) resumes when the following conditions are met:

The conditions to start operation listed above are satisfied.
The lane keeping assist system condition returns to normal.
The engine switch is turned off and on (IG) again to ensure normal operation, after the lane keeping assist system has been stopped by a system malfunction.
Center trace available is selected via operation of the steering pad switch assembly.

Operating Conditions of Lane Keeping Assist System (Vehicle Sway Warning Function)

Operation	Condition
Operating	The lane keeping assist system (vehicle sway warning function) is activated when all of the following conditions are met: Vehicle sway warning available is selected via operation of the steering pad switch assembly. The vehicle speed is approximately 50 km/h (32 mph) or more. Lane markers are detected. A system malfunction is not detected. No turn signal command is detected.
Suspended	The lane keeping assist system (vehicle sway warning function) is suspended when any one of the following conditions is met: The vehicle speed is less than approximately 50 km/h (32 mph). One side of lane markers is not detected. A turn signal command is detected. Immediately after the lane departure alert is activated. Detection of the lane width other than regulated. Detection of the curve radius other than regulated. A malfunction is detected in the lane keeping assist system. The temperature of the forward recognition camera is abnormal.
Canceled/Resume	The lane keeping assist system (vehicle sway warning function) is stopped when any one of the following conditions is met: The lane keeping assist system is malfunctioning. The engine switch is turned off. Vehicle sway warning unavailable is selected via operation of the steering pad switch assembly. The lane keeping assist system (vehicle sway warning function) resumes when the following conditions are met: The conditions to start operation listed above are satisfied. The lane keeping assist system condition returns to normal. The engine switch is turned off and on (IG) again to ensure normal operation, after the lane keeping assist system has been stopped by a system malfunction. Sway warning available is selected via operation of the steering pad switch assembly.

Operation

Condition

Operating

The lane keeping assist system (vehicle sway warning function) is activated when all of the following conditions are met:

Vehicle sway warning available is selected via operation of the steering pad switch assembly.
The vehicle speed is approximately 50 km/h (32 mph) or more.
Lane markers are detected.
A system malfunction is not detected.
No turn signal command is detected.

Suspended

The lane keeping assist system (vehicle sway warning function) is suspended when any one of the following conditions is met:

The vehicle speed is less than approximately 50 km/h (32 mph).
One side of lane markers is not detected.
A turn signal command is detected.
Immediately after the lane departure alert is activated.
Detection of the lane width other than regulated.
Detection of the curve radius other than regulated.
A malfunction is detected in the lane keeping assist system.
The temperature of the forward recognition camera is abnormal.

Canceled/Resume

The lane keeping assist system (vehicle sway warning function) is stopped when any one of the following conditions is met:

The lane keeping assist system is malfunctioning.
The engine switch is turned off.
Vehicle sway warning unavailable is selected via operation of the steering pad switch assembly.

The lane keeping assist system (vehicle sway warning function) resumes when the following conditions are met:

The conditions to start operation listed above are satisfied.
The lane keeping assist system condition returns to normal.
The engine switch is turned off and on (IG) again to ensure normal operation, after the lane keeping assist system has been stopped by a system malfunction.
Sway warning available is selected via operation of the steering pad switch assembly.

SYSTEM CONTROL

Lane Keeping Assist System Warning Operation

Function Overview (Lane Departure Alert Function)

If the function judges that the vehicle may deviate from the lane it is in, the function illuminates the indicator in the combination meter display and vibrates the steering wheel or sounds a buzzer so that the driver can take action to avoid lane departure.


*1	Buzzer
*2	Display
*3	Steering Vibration
*4	This illustration is only for explanatory purposes.

Function Overview (Steering Assist Function)
- If the lane keeping assist system judges that the vehicle may deviate from the lane it is in, the lane keeping assist system performs steering assist to help the driver correct the path of the vehicle. If the driver does not take appropriate action, the lane keeping assist system sounds a meter buzzer or vibrates the steering wheel.

Function Overview (Lane Centering Function)

The lane centering function is linked with the dynamic radar cruise control system (vehicle-to-vehicle distance control mode) and provides the required assistance by operating the steering wheel to keep the vehicle in its current lane.*

Tech Tips

*: When the dynamic radar cruise control system (vehicle-to-vehicle distance control mode) is not operating, the lane centering function does not operate. If the system detects that the steering wheel has not been operated for a fixed amount of time or the steering wheel is not being firmly gripped, a warning is displayed on the multi-information display and the function is temporarily canceled.


*1	Steering Assist
*2	Control output level
*3	This illustration is only for explanatory purposes.

Function Overview (Vehicle Sway Warning Function)

The lane keeping assist system detects drift of the vehicle within its lane, which is often the result of a driver who is tired, distracted or not looking ahead, based on the position of the vehicle within its lane and the steering inputs of the driver, to alert the driver before a lane departure or collision occurs.


*1	Warning
*2	Buzzer
*3	Display
*4	This illustration is only for explanatory purposes.

The vehicle sway warning function provides a warning to alert the driver when any of the following conditions occur:

FUNCTION

Using the meter control switches of the steering pad switch assembly, the lane keeping assist system settings functions and the vehicle sway warning functions can be customized.

*a Meter Control Switch *b LKA Main Switch

Lane Keeping Assist System Settings Functions Customization

Item (Select using the up/down button of the meter control switch)	Description	Setting (Change using the center button of the meter control switch)
Lane Center	Select to enable/disable the lane centering function	On Off
Steering Assist	Select to enable/disable steering wheel assistance	On Off
Sensitivity	Timing of the lane departure alert	High Standard
Sway Warning	Select to enable/disable the vehicle sway warning function	On Off
Sway Sensitivity	Timing of the vehicle sway warning function	High Standard Low
Alert	Warning Method	Buzzer Steering Vibration

DIAGNOSIS

If a malfunction is detected in the lane keeping assist system, the forward recognition camera cancels the lane keeping assist system, illuminates the LKA indicator in yellow and illuminates the master warning light, sounds the meter buzzer in the combination meter assembly, and displays a message on the multi-information display to inform the driver of the malfunction.
At the same time, the malfunction is stored in memory as a Diagnostic Trouble Code (DTC). When the Global TechStream (GTS) is connected to the DLC3, the DTC can be read. For details, refer to the Repair Manual.