Pre-Collision System (Diagnostics - Introduction): Other Lexus ES XV60

PRECAUTION [06/2012 - ]

1. NOTICE FOR INITIALIZATION NOTE: When disconnecting the cable from the negative (-) battery terminal, initialize the following systems after the cable is reconnected. System Name See Procedure Parking Assist Monitor System Refer to «INITIALIZATION [06/2012 - ]»(ref-598449-S08309221792014021400000) Power Trunk Lid System Refer to «INITIALIZATION [06/2012 - ]»(ref-598449-S08309221792014021400000)
2. TROUBLESHOOTING PRECAUTIONS If a terminal contact point malfunction or part installation problem occurs, removal and reinstallation of the suspected part may return the system to normal. However, be aware that the normal condition may only be temporary. Before disconnecting connectors or removing/installing parts, determine the malfunctioning area by checking and writing down the vehicle condition at the time the malfunction occurred (DTC outputs etc.). Be sure to check for DTCs related to other systems. The pre-collision system may be influenced by malfunctions in other systems.
3. HANDLING PRECAUTIONS When removing and installing the ECUs, sensors, switches or other pre-collision system related parts, perform the following: Make sure that the engine switch is off unless otherwise specified in the inspection procedure. After removal/installation, check for DTCs and confirm that a normal system code is output.

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Scheme 210

COMMUNICATION TABLE

Scheme 211

1. PRE-COLLISION SYSTEM The pre-collision system optimizes and activates occupant protection equipment (see below) to attempt to reduce damage to the vehicle and impacts to the occupants in a collision. This operation can be disabled by the pre-collision system cancel switch assembly. HINT: While the pre-collision brake operation is disabled, the PCS warning indicator light on the combination meter is turned on.
2. OUTLINE OF PRE-COLLISION SYSTEM Operating Condition Control Transmitting ECU Receiving ECU Part Operated Operates according to millimeter wave radar sensor detection Pre-collision seat belt Driving Support ECU Assembly Seat belt control ECU Front seat outer belts Operates according to millimeter wave radar sensor detection Pre-collision brake assist Driving Support ECU Assembly Brake actuator assembly (skid control ECU) Brake assist system Operates when sudden braking or skidding occurs Pre-collision seat belt Brake actuator assembly (skid control ECU) Seat belt control ECU Front seat outer belts Operates according to millimeter wave radar sensor detection Pre-collision brake Driving Support ECU Assembly Brake actuator assembly (skid control ECU) Brake system When operating according to millimeter wave radar sensor detection: The millimeter wave radar sensor detects vehicles and other objects on the road in front of the user's vehicle. The driving support ECU assembly determines if the possibility of a collision is high of if a collision is unavoidable based on object position, speed and track information. If the driving support ECU assembly determines that the possibility of collision is high of that a collision is unavoidable, it transmits this information to the following areas using CAN communication: Seat belt control ECU (initiates control of pre-collision seat belts) Brake actuator assembly (skid control ECU) (activates pre-collision brake assist system) Brake actuator assembly (skid control ECU) (activates pre-collision brake) When operating as a result of sudden braking or skidding: The brake actuator assembly (skid control ECU) uses brake pressure information and other data to determine if the driver has suddenly applied the brakes or lost control of the vehicle. If so, the brake actuator assembly (skid control ECU) sends a signal to the seat belt control ECU through CAN communication and the pre-collision seat belts operate.
3. OUTLINE OF PRE-COLLISION SEAT BELT CONTROL The pre-collision seat belts operate depending on what the millimeter wave radar sensor detects, or whether sudden braking or skidding has occurred. The pre-collision seat belts motor retracts the seat belt to enhance pretensioner effectiveness. Operating condition Refer to the millimeter wave radar sensor and sudden braking or skidding descriptions under "Outline of Pre-collision System" (see above).
4. OUTLINE OF PRE-COLLISION BRAKE ASSIST CONTROL The pre-collision brake assist operates depending on what the millimeter wave radar sensor detects. The system then enters standby mode before a collision. When the driver depresses the brake pedal, brake fluid pressure is increased to improve fluid pressure response and improve the rate of deceleration. Operating condition Refer to the millimeter wave radar sensor description under "Outline of Pre-collision Safety System" (see above). When the driver depresses the brake pedal after the driving support ECU assembly determines that there is a collision is high possibility of collision: Brake fluid pressure is increased at the same time the driver depresses the brake pedal.
5. OUTLINE OF PRE-COLLISION BRAKE CONTROL The pre-collision brake operation is performed depending on what the millimeter wave radar sensor detects. Operating condition Refer to the millimeter wave radar sensor description under "Outline of Pre-collision System" (see above). When the driving support ECU assembly determines that a collision is unavoidable, the system performs brake control (pre-collision brake operation) to reduce the vehicle speed. When a preceding vehicle is detected, the system advances brake control (pre-collision brake operation) activation timing in order to increase speed reduction performance.
6. OPERATIVE CONDITION AND INOPERATIVE CONDITION OF EACH CONTROL (REVIEW) HINT: Each function will operate when all items marked (o) are satisfied. Pre-collision Seat Belt*1 Pre-collision Seat Belt*2 Pre-collision Brake Assist*2 Pre-collision Brake*2 When engine switch is on (IG) o o o o No malfunctions in related components. Refer to «PROBLEM SYMPTOMS TABLE [06/2012 - ]»(ref-598707-S18068329912014021400000) o o o o When front seat belt(s) is/are fastened o o - - Operates when the vehicle speed is 30 km/h (19 mph) or more, regardless of relative speed o - - - Operates when the vehicle speed is 5 km/h (4 mph) or more and relative speed is 30 km/h (19 mph) or more - o - - Operates when the vehicle speed is 15 km/h (10 mph) or more and relative speed is 15 km/h (10 mph) or more - - - o Operates when the vehicle speed is 30 km/h (19 mph) or more and relative speed is 30 km/h (19 mph) or more - - o - When pre-collision system has not been disabled using the pre-collision system cancel switch assembly o o o o When the brake pedal is depressed - - o - *1: Operates when sudden braking or skidding is detected. *2: Does not operate in the following situations. When the vehicle collides with an object outside the detection range of the millimeter wave radar sensor (side collision, rear collision, etc.) When the millimeter wave radar sensor cannot detect a possible collision object o: Main basis for operation -: Not main basis for operation
7. CASES OF UNNECESSARY PRE-COLLISION SYSTEM OPERATION When the millimeter wave radar sensor detects an object in front of the vehicle under the conditions described below, the driving support ECU may determine that the possibility of a collision is high or if a collision is unavoidable, and activate the pre-collision system. This activation of the system is not abnormal. TEXT IN ILLUSTRATION *a There are objects on the side of the road at the beginning of a curve (a guardrail, street lamp, billboard, etc.). *b Passing an oncoming vehicle on a curve. *c There is an oncoming vehicle when making a left turn. *d Crossing a narrow metal bridge. *e There are metal objects on the road. *f Approaching a leading vehicle suddenly. *g Electrical toll collection gate (React to bar.) *h Crossing an overpass, traffic sign, signboard *i The vehicle height drastically changes (nose-up, nose-down). *j Misalignment of millimeter wave radar sensor. (reinstallation, collision, etc) *k There is a billboard or sign at the top of an incline. *l There are metal objects at the bottom of a decline (a metal plate covering road construction, a mesh drain cover, a manhole, etc.) *m Roughness in road surface. - - HINT: The pre-collision system will not activate when approaching safety cones or other plastic objects as they cannot be detected by the millimeter wave radar sensor. The pre-collision system may or may not activate when the millimeter wave radar sensor detects the following objects: people, bicycles, motorcycles, trees, animals and snow fences, etc. Detection performance may deteriorate in the following conditions. Another vehicle suddenly cuts in traveling direction of driver's own vehicle In severe weather such as heavy rain, fog, snow or a sand storm Vehicle is skidding sideways while VSC is not operating Vehicle height changes significantly (front of vehicle inclined either upward or downward) Millimeter wave radar sensor is misaligned (due to reinstallation or collision) Object Type Example Objects that cannot be detected Plastic items (safety cones) Objects that cannot be detected in a stable manner People, bicycles, motorcycles, trees, animals, snow fences, etc.

FAIL-SAFE CHART [06/2012 - ]

HINT

The pre-collision system fail-safe function and details are indicated in the table below.

*1: The overheating prevention function operates when the seat belt control ECU detects a rise in seat belt temperature because of excessive seat belt operation.