Toyota Tacoma 2015-2018 Service Manual: System Description

Toyota Tacoma 2015-2018 Service Manual / Cruise Control / Lane Departure Alert System / 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
1: for Vacuum Brake Booster 2: for Hydraulic Brake Booster
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 Cable with Sensor Sub-assembly	Sends the turning angle of the steering wheel to the forward recognition camera
Skid Control ECU (Brake Actuator Assembly)1 Skid Control ECU (Master Cylinder Solenoid)2	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

Parts Location

PARTS LOCATION ILLUSTRATION *A for Vacuum Brake Booster *B for Hydraulic Brake Booster *1 SKID CONTROL ECU (BRAKE ACTUATOR A ...

System Diagram

SYSTEM DIAGRAM Communication Table Sender ECU Receiver ECU Signal Line *1: for Vacuum Brake Booster *2: for Hydraulic Brake Booster ...

Other materials:

Transmission Fluid Temperature Sensor "B" Circuit Short to Battery or Open (P274015)
DESCRIPTION The No. 2 ATF temperature sensor is installed in the transmission valve body assembly. If the ECM detects an abnormally high ATF temperature near this sensor, it illuminates the warning indicator. HINT: The temperature of ATF easily rises when towing, climbing hills, in traffic, ...

AVC-LAN Circuit
DESCRIPTION Each unit of the navigation system connected to the AVC-LAN (communication bus) transfers the switch signals using the AVC-LAN. If a short to +B or short to ground occurs in the AVC-LAN, the navigation system will not function normally because communication is not possible. WIRING ...

Accumulator Low Pressure (C1452)
DESCRIPTION DTC Code DTC Detection Condition Trouble Area C1452 After braking, the fluid pressure inside the accumulator is below the threshold within 3.2 seconds. Hydraulic circuit Accumulator pressure sen ...