LANE-KEEP ASSIST SYSTEM

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Purpose

Warning

•  The lane-keep assist system is a supplementary system which helps the driver stay within the vehicle lanes, but it is not an automatic driving system. If the driver takes his or her hands off the steering wheel, the lane-keep assist system will not operate. In all situations, always make it your responsibility as a driver to check the vehicle's surroundings and drive the vehicle correctly.

•  The detection ability of the lane-keep assist system is limited. Over reliance on the lane-keep assist system leading to the steering wheel being mistakenly operated could result in an accident and serious injury or death. Do not rely completely on the lane-keep assist system and always stay on course using the steering wheel.

•  The lane-keep assist system may not operate normally under the following conditions.

―  Poor vehicle lane line visibility due to adverse weather (rain, snow, fog)

―  Poor vehicle lane line visibility due to backlight, snow on the road, water puddles, road ruts

―  Poor vehicle lane line visibility due to cracks and fissures in the vehicle lane

―  Vehicle lane lines intersect with complexity due to additions or reductions of travel lanes

―  Vehicle lane marking is not completely erased after road maintenance, two or more lane lines next to each other

―  Vehicle lane lines not recognized due to vehicle ahead

―  Vehicle is driven on sharp curve

―  Vehicle is Driven on slippery road

―  Driving on road with extremely narrow/wide driving lanes

―  Tire pressure is not adjusted to specified value

―  Tires other than specified size installed

―  No vehicle lane lines

Caution

•  If the forward sensing camera (FSC) aiming is not completed correctly, the forward sensing camera (FSC) cannot record the camera shooting angle and the lane-keep assist system may not operate normally. When performing the following servicing, always perform the forward sensing camera (FSC) aiming. In addition, for the FSC aiming procedure, refer to the [FORWARD SENSING CAMERA (FSC) AIMING] in the Workshop Manual.

―  Forward sensing camera (FSC) replacement

―  Windshield replacement

Note

•  If a malfunction occurs in the EPS system, the lane-keep assist system will not operate.

Functions

Steering wheel operation assist

•  “Late” mode (lane departure prevention support)

―  If the possibility of a lane departure increases due to the driver's carelessness, the system assists the driver in preventing a lane departure by operating the steering wheel.

•  "Early" mode (driving lane trace support)

―  When the lane-keep assist system is set to the "Early" condition using the personalization feature, driver fatigue resulting from long-distance driving is reduced by the system operating the steering wheel to assist the driver in remaining in the center of the driving lane.

Lane-keep assist system warning

•  Steering wheel vibration or a warning sound activates and the warning screens are indicated in the multi-information display or the active driving display to warn the driver.

•  The following lane-keep assist warning settings can be changed. (See i-ACTIVSENSE PERSONALIZATION.)

―  Operation/non-operation (during steering wheel operation assist)

―  Warning activation timing (during steering wheel operation assist non-operation)

―  Warning sensitivity (during steering wheel operation assist non-operation)

―  Type of warning (steering wheel vibration/rumble strip sound^*1/beep sound)

―  Strong/weak steering wheel vibration or warning sound volume

Construction

Structural View

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System Wiring Diagram

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Block Diagram

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Operation

―  Lane-keep assist system ON

―  Driving at vehicle speed of approx. 60 km/h {37 mph} or more

―  Forward sensing camera (FSC) detects white lines (yellow lines) on both the right and left sides

―  Driver is operating steering wheel

Note

•  European (L.H.D., R.H.D.) specs:

―  When the ignition is switched OFF, the lane-keep assist system becomes operational the next time the ignition switched ON.

•  Except European (L.H.D., R.H.D.) specs:

―  When the ignition is switched OFF, the system status before it was turned off is maintained. For example, if the ignition is switched OFF with the lane-keep system operable, the system will be operable when the ignition is switched ON the next time.

―  Forward sensing camera (FSC) cannot detect white lines (yellow lines)

―  Forward sensing camera (FSC) detects only a white line (yellow line) on either the left or right

―  Vehicle speed is less than approx. 60 km/h {37 mph}

―  ABS/DSC is operating

―  DSC is off

―  Vehicle is driven on sharp curve

―  Driving on winding roads

―  Driver takes his or her hands off steering wheel

Note

•  The forward sensing camera (FSC) determines if the driver has taken his or her hands off the steering wheel based on the signal from the torque sensor. A torque sensor signal is output to CAN via the TCM.

•  While the driver is not operating the steering wheel, an uneven road is input from the tires to the torque sensor. The forward sensing camera (FSC) determines that the driver has taken his or her hands off the steering wheel based on the sudden increase in torque or input of a minute, irregular signal at that time.

•  If this condition continues for the preset period, the forward sensing camera (FSC) displays the warning indication in the display to warn the driver.

―  The turn switch is operated. (the steering wheel operation assist on)

―  After the turn switch is operated, the vehicle lane is changed within 3 s. (the steering wheel operation assist off)

―  The steering wheel is turned at a certain angle or more, and an avoidance maneuver is performed or the vehicle lane is changed.

―  The accelerator pedal is depressed a certain amount or more.

―  The brake pedal is depressed.

Note

•  When all of the operation conditions are met after driving, the lane-keep assist system is enabled automatically.

System conditions display table

Lane-keep assist system condition	Condition	Lane-keep assist system indication	Multi-information display indication	Active driving display indication
OFF	System off	No display	No display	No display
ON	Vehicle lane lines are recognized on both sides at a vehicle speed of approx. 60 km/h {37 mph} or more
	While warning is triggered*
	Vehicle speed is approx. 60 km/h {37 mph} or less			No display
	Vehicle lane lines are not recognized or vehicle lane line is recognized on either left or right side at a vehicle speed of approx. 60 km/h {37 mph} or more			No display
	Forward sensing camera (FSC) detects camera fogging			No display
	Forward sensing camera (FSC) detects that the camera is dirty			No display
	Malfunction in lane-keep assist system occurred			No display
	Malfunction in forward sensing camera (FSC) occurred			No display
	Driver takes his or her hands off steering wheel

Note

•  A warning message in the center display and multi-information display are displayed. For the message content and verification method of the center display, refer to the CENTER DISPLAY. (See CENTER DISPLAY [WITH CENTER DISPLAY].)

Steering wheel operation assist

•  "Late" condition operation (lane departure prevention support)

―  When the vehicle approaches to white lines (yellow lines), the forward sensing camera (FSC) calculates the steering angle required for the prevention of a lane departure and outputs a steering wheel operation assist request signal to the EPS CM.

―  The EPS CM energizes the EPS motor to generate assist torque (maximum 5 N·m {51 kgf·cm, 44 in·lbf}) and supplement the insufficient steering angle for the prevention of a lane departure based on the steering wheel operation assist request signal.

―  When the driver performs the prevention operation during steering wheel operation assist, the driver's operation is given priority.

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•  "Early" condition operation (driving lane trace support)

―  The forward sensing camera (FSC) calculates the steering angle required for driving the vehicle near the center of the driving lane based on the right and left white lines (yellow lines).

―  If the steering angle according to the driver's steering wheel operation is insufficient for the calculated value of the forward sensing camera (FSC), a steering wheel operation assist request signal is output to the EPS CM.

―  The EPS CM energizes the EPS motor to generate assist torque (maximum 4 N·m) and assist the driver's steering wheel operation based on the steering wheel operation assist request signal.

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Lane departure warning

•  When the vehicle contacts warning-trigger line, a lane departure warning triggers for 0.5 s. For details on the warning-trigger line, refer to the [FORWARD SENSING CAMERA (FSC)]. (See FORWARD SENSING CAMERA (FSC).)

•  If the warning is triggered one time, the warning will not trigger again until the vehicle travels within the warning-trigger lines for a period of 3 s (If steering wheel operation assist is turned off, the warning will not trigger again until the vehicle travels within the warning-trigger lines for a period of 1.5 s.).

•  If the forward sensing camera (FSC) determines that the vehicle has contacted a warning-trigger line, it sends a warning indication request signal to the instrument cluster.

•  When the instrument cluster receives the warning indication request signal, it displays the warning screen in the active driving display or the multi-information display.

•  The forward sensing camera (FSC) sends the following signals according to the type of the warning-trigger set using the personalization feature.

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―  Steering wheel vibration

•  A steering wheel vibration request signal is sent to the EPS CM.

•  When the EPS CM receives the steering wheel vibration request signal, it energizes the EPS motor to vibrate the steering wheel.

―  Rumble strip sound

•  A warning sound request signal is sent to the connectivity master unit (CMU).

•  When the CMU receives the warning sound request signal, it sends the warning sound request signal to the tuner and amp unit (TAU). The TAU outputs the rumble strip sound from the front left or right door speaker.

―  Beep sound

•  A warning sound request signal is sent to the instrument cluster.

•  When the instrument cluster receives the warning sound request signal, it operates the buzzer built into the instrument cluster. For the buzzer operation, refer to the [LANE DEPARTURE WARNING SOUND]. (See LANE DEPARTURE WARNING SOUND.)

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Note

•  When the forward sensing camera (FSC) can detect either left or right white line (yellow line), the lane-keep assist system is performed. However, the steering wheel operation assist and warning cannot be activated only when the vehicle deviates on the side where the white line (yellow line) is being detected.

•  The driver's steering wheel operation assist is performed so that the vehicle remains near the center of the driving lane under the "Early" operation condition, however, an appropriate assist may not be performed depending on conditions such as the road curvature, road slope and undulations, and vehicle speed.

•  The timing at which the steering wheel operation assist is performed and the lane-keep assist system warning is activated varies.

•  If the driver takes his or her hands off the steering wheel, alarm sound is activated and a message is indicated in the multi-information display. For the message, refer to the system conditions indication table.