EMERGENCY LANE KEEPING [ROAD KEEP ASSIST] [(E)]

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Outline

• The system helps in avoiding departure from the road by providing steering assistance if the vehicle may be deviating from the road.

• The system detects the boundary between the road and the gravel shoulder, boundary between the road and the grass shoulder, guardrails, road curbs, and roadside walls while the vehicle is being driven and if it determines that the vehicle may deviate from the road, the system operates the electric power steering and assists the driver’s steering wheel operation.

Warning

• The emergency lane keeping [road keep assist] is not an autonomous driving system. In addition, because the system is not designed to compensate for not paying attention to the conditions ahead, over-reliance on the system could result in an accident.

• The detection ability of the emergency lane keeping [road keep assist] function is limited. Always stay on course using the steering wheel and drive with care.

• Do not use the emergency lane keeping [road keep assist] under the following conditions. Otherwise, it could lead to an accident.

― Vehicle is driven on slippery roads such as icy or snow-covered roads, and unpaved roads

― Tires other than specified size, such as temporary spare tire, are used

― Tires without sufficient groove are used

― Tire pressure not adjusted to specified value

― Towing camping trailer or boat trailer

― Tire chains are installed

Caution

• To ensure that the emergency lane keeping [road keep assist] operates normally, heed the following precautions.

― Do not modify the suspension

― Always install tires of the specified size to all four wheels

Note

• The emergency lane keeping [road keep assist] may not operate normally under the following conditions.

― Road edge such as curbs without height or road boundaries with no difference in road surface color is invisible

― Road edge cannot be detected due to weather (rain, fog, snow)

― Road edge and indiscernible lines such as road maintenance markings, guardrail shadows, residual snow, or water-filled road ruts are visible

― Surrounding brightness suddenly changes such as when entering or exiting tunnel

― Road width is narrow

― Vehicle is tilted by heavy cargo in luggage compartment or rear seat

― At night, headlight lens is dirty and illumination is weak or its optical axis is deviated

― Road is winding

― Vehicle is shaken heavily due to hitting road bump

― Poor road edge visibility due to vehicle ahead traveling near road edge

― Windshield is dirty or fogged

― Vehicle is subjected to strong light from vehicle front (sunlight or headlights (high beam) from on-coming vehicle)

Structural View

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Function

• The body control module (BCM) and the EPS control module assist the driver in operating the steering wheel based on the boundary between the road and the gravel shoulder, the boundary between the road and the grass shoulder, guardrails, road curbs, and roadside walls detected by the forward sensing camera (FSC). For details on the forward sensing camera (FSC), refer to the [FORWARD SENSING CAMERA (FSC)]. (See FORWARD SENSING CAMERA (FSC) [(E)].)

• With the emergency lane keeping [road keep assist], the steering wheel operation assist can be changed between operational and non-operational using the personalization features. For details on personalization features, refer to [PERSONALIZATION FEATURES] in the workshop manual.

Steering wheel operation assist

• The system assists the driver in operating the steering wheel to prevent a departure from the road if the possibility of a road departure increases.

• The multi-information display notifies the driver which direction the steering wheel operation is being assisted.

Emergency lane keeping [road keep assist] warning

• When the system is operated under the following conditions, the warning sound from the notification and warning speaker is activated to alert the driver.

― Steering wheel operation assist performed continuously for 10 s or more

― Steering wheel operation assisted 2 or more times within continuous interval of 180 s without driver intervention

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System conditions display

System conditions display table

Emergency lane keeping [road keep assist] status	Status	Emergency lane keeping (ELK) OFF indicator light	i-ACTIVSENSE warning light	Multi-information display
OFF	System off	ON	OFF	No display
ON	Operation conditions are not met	OFF	OFF	No display
	Operation conditions are met, but no vehicle lane lines are detected	OFF	OFF	No display
	Operation conditions are met and only vehicle lane lines on left side are detected	OFF	OFF	No display
	Operation conditions are met and only vehicle lane lines on right side are detected	OFF	OFF	No display
	Operation conditions are met and vehicle lane lines on both sides are detected	OFF	OFF	No display
	Steering controlled to right	OFF	OFF
	Steering controlled to left	OFF	OFF
	Temporarily disabled	OFF	OFF	No display
	System malfunction	ON	ON

System wiring diagram

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Block diagram

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Operation

• The emergency lane keeping [road keep assist] operates when all of the following conditions are met.

― Driving at vehicle speed of approx. 60 km/h {37 mph} or more and less than approx. 200 km/h {124.0 mph}

― Driving straight ahead or on gentle curves

― Boundary between road and gravel shoulder, boundary between road and grass shoulder, guardrails, road curbs, and roadside walls on either side are detected

• Even if the emergency lane keeping [road keep assist] is turned on, it goes on stand-by under any of the following conditions.

― Vehicle speed is less than approx. 60 km/h {37 mph} or 200 km/h {124.0 mph} or more

― Boundary between road and gravel shoulder, boundary between road and grass shoulder, guardrails, road curbs, and roadside walls cannot be detected

― DSC/TCS is operated

• The emergency lane keeping [road keep assist] determines that the driver is performing the following driving operations, and cancels the steering wheel operation assist.

― Turn switch is operated

― Avoidance maneuver is performed

― Accelerator pedal is depressed a certain amount or more

― Brake pedal is depressed

Note

• When the operation conditions are met after driving, the emergency lane keeping [road keep assist] automatically returns to the operational status.

• If a malfunction in the emergency lane keeping [road keep assist], forward sensing camera (FSC), or EPS control module occurs, the emergency lane keeping [road keep assist] temporarily turns off.

• The emergency lane keeping [road keep assist] can be changed between operational and non-operational using the personalization features. For details on personalization features, refer to [PERSONALIZATION FEATURES] in the workshop manual.

Steering wheel operation assist

• When the vehicle approaches the white lines (yellow lines) of the vehicle lane, the body control module (BCM) calculates the steering angle required for the prevention of a road departure and outputs a steering wheel operation assist request signal to the EPS control module.

• The EPS control module energizes the EPS motor to generate assist torque and supplement the insufficient steering angle for the prevention of a road 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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Note

• When the forward sensing camera (FSC) can detect the boundary between the road and the gravel shoulder, the boundary between the road and the grass shoulder, guardrails, road curbs, and roadside walls on either side, the emergency lane keeping [road keep assist] operates. However, the steering wheel operation assist cannot be performed to a side where the boundary between the road and the gravel shoulder, the boundary between the road and the grass shoulder, guardrails, road curbs, and roadside walls cannot be detected.