Toyota Tundra Service Manual: System Description

SYSTEM DESCRIPTION

LANE DEPARTURE ALERT SYSTEM DESCRIPTION

(a) The lane departure alert system is a system which uses the forward recognition camera to recognize and determine the lane and the position of the vehicle when the vehicle is being driven on highways and other roads with white (yellow) lines. Based on the situation, this system provides information and warnings for the driver.

SYSTEM SPECIFICATION

Operation speed

Approximately 50 km/h (32 mph) or more.

Operation lane width

Approximately 3 m (10 ft.) or more.

Operation curve radius

Approximately 150 m (493 ft.) or more.

OPERATING CONDITIONS

(a) Lane departure alert function can operate if all of the following base conditions are met:

  • The lane departure alert main switch is turned on.
  • The vehicle speed is within the operation conditions.
  • The vehicle is driving in a lane with a width within the operation conditions.
  • The vehicle is driving on a straight road or a road with a slight curve.
  • Lane markers are detected.
  • The lane departure alert system has no malfunctions.
  • The turn signal switch is off.

(b) Vehicle sway warning can operate if all of the following base conditions are met:

  • The lane departure alert main switch is turned on.
  • "Sway Warning" on the settings screen on the multi-information display is set to "ON".
  • The vehicle speed is within the operation conditions.
  • The vehicle is driving in a lane with a width within the operation conditions.
  • The vehicle is driving on a straight road or a road with a slight curve.
  • The lane departure alert system has no malfunctions.
  • Lane markers are detected.

CONTROL OF EACH FUNCTION

(a) Lane departure alert function:

(1) Sensitivity: "Standard (graphic display)"

A warning is output when a front wheel starts to cross a lane marker.

HINT:

When the deviation speed (lateral travel speed) is slow, the warning may be output after the front wheel crosses over the lane marker.

(2) Sensitivity: "High (graphic display)"

A warning is provided when a front wheel nears a lane marker.

HINT:

When the deviation speed (lateral travel speed) is slow, the warning may be provided when the front wheel starts to cross the lane marker.

(b) Vehicle sway warning:

(1) A warning is output when any of the following occurs:

  • The vehicle repeatedly deviates from its lane
  • The vehicle drifts within its lane when the driver is inattentive

FUNCTION OF COMPONENTS

COMPONENTS

FUNCTION

Forward Recognition Camera

  • Detects lane markers and objects on the road ahead using the image captured by the monocular camera and generates information about the road
  • Sends request signals to the combination meter assembly to display lane departure alert indicators and messages and sound the LDA buzzer
  • Stores customize settings information

Lane Departure Alert Main Switch (Steering Pad Switch Assembly)

Turns on/off the lane departure alert system

Customize Switch (Steering Pad Switch Assembly)

Changes the customize settings of the lane departure warning function and vehicle sway warning function

Combination Meter Assembly

  • Displays messages on the multi-information display and turns on lane departure alert indicators based on request signals from the forward recognition camera
  • Sounds the LDA buzzer based on request signals from the forward recognition camera
  • Sends meter tolerance and turn signal switch operation signals to the forward recognition camera
  • Sends customize settings information to the forward recognition camera

Spiral with Sensor Cable Sub-assembly

Sends the turning angle of the steering wheel to the forward recognition camera

Skid Control ECU (Brake Actuator Assembly)

Sends the wheel speed, yaw rate zero point, brake operation status and other information to the forward recognition camera

Yaw Rate and Acceleration Sensor (Airbag Sensor Assembly)

Sends signals received from the yaw rate and acceleration sensor to the forward recognition camera

ECM

Sends the accelerator pedal opening angle signal to the forward recognition camera

Millimeter Wave Radar Sensor Assembly

Sends the preceding vehicle information to the forward recognition camera

Main Body ECU (Multiplex Network Body ECU)

Sends the country specification information to the forward recognition camera

Network Gateway ECU

Gateway function of CAN communication

SYSTEM INOPERATIVE CONDITIONS

(a) The lane departure alert system may not operate in any of the following conditions:

  • When driving through an area with no lane markers or such as a tollbooth
  • When lane markers are obscured or cannot be recognized due to backlight, bad weather or standing water
  • When driving in a location where the light level changes rapidly, such as the entrance to or exit from a tunnel
  • When the tires are excessively worn or the tire inflation pressure is insufficient
  • When non-standard tires are used (incorrect tire size or tire maker)
  • When winter tires or a spare tire is used
  • When a non-standard suspension is installed
  • When the road is partially covered in snow
  • When there are shadows on the road running parallel with the lane markers
  • When the lane markers are Bott's dots (raised pavement markers), stone, etc.
  • When there are markings on the road due to road repairs, etc.
  • When driving through a road construction area
  • When turning a sharp corner
  • When driving on a road that is branching or merging
  • When a lane is extremely narrow or wide
  • When driving on a particularly bright road surface, such as concrete
  • When driving on a road surface that is bright due to reflected sunlight or the headlights of oncoming vehicles
  • When driving on a road surface that is wet due to rain, standing water, etc.
  • When driving on a winding or uneven road
  • When the distance between the vehicle and the preceding vehicle is extremely short
  • When the vehicle experiences strong up-and-down motion such as when driving over a joint in the road surface or on an extremely rough road
  • The vehicle is extremely tilted due to carrying heavy luggage or having improper tire pressure
  • The vehicle is struck by a crosswind
    Steering Pad Switch Circuit

    System Diagram

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