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Home >> Lexus >> 2010 >> LS 460 RWD V8-4.6L (1UR-FSE) >> Repair and Diagnosis >> Accessories and Optional Equipment >> Collision Avoidance and Parking Assist Systems >> Description and Operation >> Pre-Collision System (w/ Driver Monitor Camera)

Pre-Collision System (w/ Driver Monitor Camera)





PRE-COLLISION: PRE-COLLISION SYSTEM (w/ Driver Monitor Camera): SYSTEM DIAGRAM


















SYSTEM DESCRIPTION

1. PRE-COLLISION SYSTEM DESCRIPTION

(a) The pre-collision system detects vehicles and obstacles in front of the vehicle and performs the following: 1) optimally uses system controls to avoid crashes, and 2) uses system controls to reduce impact during a crash.

2. PRE-COLLISION DETECTION OUTLINE

(a) Front crash detection

(1) The driving support ECU receives information about vehicles and obstacles in front of the vehicle from the front millimeter wave radar sensor and object recognition camera. Then, based on vehicle speed, road conditions and obstacle location, the driving support ECU determines, in advance, the risk of a crash and if a crash is unavoidable.

(2) The driver monitor camera detects the direction that the driver's head is facing. When a potential crash is detected and the camera determines that the driver's head is not facing forward, it activates the pre-collision controls in advance.

(b) Sudden braking detection

(1) The skid control ECU activates the pre-collision seat belts when it detects sudden braking. Sudden braking is determined based on brake oil pressure and other information from the master cylinder pressure sensor.

(c) Vehicle control impossible judgment

(1) The pre-collision seat belts are activated when it is determined that there is a high probability that the vehicle cannot be controlled. The judgment is based on vehicle stability information from the yaw rate sensor and steering angle sensor.

(d) Component





3. PRE-COLLISION SYSTEM CONTROL DESCRIPTION





4. PRE-COLLISION ALARM CONTROL

(a) When the system determines that there is a risk of colliding with an obstacle in front of the vehicle, the multi-information display and warning buzzer are used to warn the driver and help with crash avoidance.

5. PRE-COLLISION SEAT BELT CONTROL

(a) When the system determines that a crash with an obstacle is unavoidable, that sudden braking has occurred, or that vehicle control is impossible, the system performs seat belt control. During seat belt control, slack in the seat belts is reduced to increase occupant restraint and aid the pretensioner.

6. PRE-COLLISION BRAKE ASSIST CONTROL

(a) When the system determines that there is a risk of colliding with an obstacle in front of the vehicle, brake assist is set to standby mode. Then, when the driver depresses the brake pedal, the hydraulic brake pressure is increased to improve braking effectiveness.

7. AIR SUSPENSION CONTROL

(a) When it is determined that there is a risk of colliding with an obstacle in front of the vehicle, the AVS is operated to control the damping force, suppress nose diving and rolling, and support collision avoidance through steering.

8. VARIABLE GEAR RATIO STEERING CONTROL

(a) When the system determines that there is a risk of colliding with an obstacle in front of the vehicle, the Variable Gear Ratio Steering (VGRS) system is set to standby at an optimum steering ratio (i.e., increasing power steering) for collision avoidance.

9. PRE-COLLISION BRAKE CONTROL

(a) When the system determines that a crash with an obstacle is unavoidable, the system performs brake control to reduce the vehicle speed.

10. PRE-COLLISION BRAKE CANCEL SWITCH

(a) When the pre-collision brake cancel switch in the glove box is turned ON, the pre-collision alarm and pre-collision brake do not operate.

HINT
While the pre-collision brake cancel switch is ON, the combination meter's PCS indicator light blinks.

11. PRE-COLLISION SYSTEM OPERATING CONDITION





HINT
* o: Operation
* X: Not operation
* *1: Inoperative parts are different depending on malfunction areas
* *2: Only operates when seat belt is fastened
* *3: Pre-collision seat belts may operate when brakes are suddenly applied
12. PRECAUTION FOR FRONT MILLIMETER WAVE RADAR SENSOR AND OBJECT RECOGNITION CAMERA SENSOR

(a) When the front millimeter wave radar sensor and object recognition camera sensor detect an object in front of the vehicle under the conditions described below, the driving support ECU may determine that a collision is unavoidable, and activates the pre-collision system. However, this is not abnormal.





HINT
* The pre-collision system does not activate when the pre-collision sensor detects safety cones and other plastic objects.
* The pre-collision system may or may not activate when the pre-collision sensor detects the following objects: people, bicycles, motorcycles, trees, animals and snow fences.





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