System Description [08/2013 - ]

WARNING: This page is about a different car, the 2014 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.

LANE DEPARTURE ALERT DESCRIPTION
1. The lane departure alert system uses the lane departure warning camera's image of the road in front to detect lane marker on either side of the vehicle. If the system detects that the vehicle is about to move out of its lane, the system uses the warning buzzer and multi-information display to warn the driver.
  However, in the following conditions, the lane departure alert system may not function normally.
  - Vehicle is near toll booths or similar areas
  - Road has no lane markers
  - Lane markers are cracked
  - Road has yellow lines
  - There is a shadow on either of the lane markers
  - As a result of reflections, the road surface is bright
  - Road has a reflective surface such as concrete
  - Area where brightness changes suddenly, such as entrances and exits of tunnels or similar areas
  - Bright light is directed at sensor
  - Incline of the road varies, winding road or other type of road where road surface is irregular
  - Bad weather
  - Frozen or snowy roads
  - Water or other liquid on road surface

SYSTEM OPERATION

Lane departure warning function:

The lane departure warning function operates when the lane departure alert main switch is on, the vehicle speed is between 50 km/h (32 mph) and 220 km/h (138 mph), and lane markers on the road surface are detected. With the departure warning function operating, if the vehicle is about to move out of the lane and this is detected by the lane departure warning camera, the system uses the warning buzzer and the multi-information display to warn the driver.

HINT:

This function only provides suggestions for lane departure avoidance. This function does not automatically move the vehicle back into the lane.

If any of the following conditions are met while the lane departure alert system is operating, system operation will be interrupted.

Lane Departure Warning Function Operation Interruption Condition	Lane Departure Warning Function Operation Return Condition
When vehicle speed is less than 50 km/h (32 mph), or more than 220 km/h (138 mph)	When vehicle speed is between 50 km/h (32 mph) and 220 km/h (138 mph)
When turn signal light switch is operated	When turn signal light switch is turned off
When lane departure warning camera cannot detect lane markers	When lane departure warning camera can detect lane markers
After lane departure warning has been issued	When the vehicle moves back into its lane, or a few seconds have passed since warning was issued

If any of the following conditions is met while the lane departure alert system is operating, system operation will be suspended.

Lane Departure Warning Function Operation Suspension Condition	Lane Departure Warning Function Operation Restart Condition
When lane departure alert main switch is off	When lane departure alert main switch is on
When system operation is interrupted	When the system returns to normal
When the system is malfunctioning	When the power switch is turned on (IG), normal system operation is confirmed

If the following condition are met, the lane departure warning camera sounds a warning buzzer, turns off the lane departure alert indicator, displays "LDA not available" on the multi-information display, and temporarily suspends lane departure alert system operation.

Fig 1: Identifying Lane Departure Alert Display (1 Of 2)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
- A high lane departure warning camera temperature is detected
If the following condition is met, the lane departure warning camera sounds a warning buzzer, turns off the lane departure alert indicator, displays "Check LDA System" on the multi-information display, and suspends lane departure alert system operation.

Fig 2: Identifying Lane Departure Alert Display (2 Of 2)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
- Lane departure alert system is malfunctioning

FUNCTION OF MAIN COMPONENTS

Item	Outline
Lane Departure Warning Camera	Takes an image of the road ahead and processes the image. Based on the results, display information and a buzzer request signal are sent to the combination meter assembly and skid control buzzer assembly. Controls display information for the multi-information display and buzzer sound condition Monitors the lane departure alert main switch signal Monitors the lane departure alert system malfunctions and records diagnostic information
Steering Pad Switch Assembly (Lane Departure Alert Main Switch)	Turns the lane departure alert system on/off
Headlight Dimmer Switch Assembly	Sends the operation condition of the turn signal light switch to the lane departure warning camera
Combination Meter Assembly	The lane departure alert indicator turns on when the lane departure alert system main switch is on When the lane departure alert system detects a malfunction, the warning buzzer sounds once to inform driver When the lane departure warning function is operating, lane markers are displayed to inform the driver of lane detection When the lane departure warning camera detects a malfunction signal, a message is displayed on the multi-information display to inform driver
Airbag Sensor Assembly (Yaw Rate and Acceleration Sensor)	Detects the yaw rate of the vehicle and transmits a signal to the lane departure warning camera
Skid Control ECU (Brake Booster with Master Cylinder Assembly)	Sends vehicle speed information to the lane departure warning camera
Vehicle Speed Sensor	Sends a vehicle speed signal to the skid control ECU (brake booster with master cylinder assembly), and then to the lane departure warning camera
Skid Control Buzzer Assembly	Sounds a buzzer upon receiving a signal from the lane departure warning camera
Power Management Control ECU	Sends a shift position R signal to the lane departure warning camera
Main Body ECU (Multiplex Network Body ECU)	Sends country specification information to the lane departure warning camera