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System Description [11/2015 - 06/2017]

  1. PRE-COLLISION SYSTEM DESCRIPTION 
    1. The pre-collision system determines the possibility of a collision according to information such as the position of the obstacle and its relative speed, and provides optimal control to avoid a collision and control to reduce the impact during a collision via warnings, brake assist and automatic braking.
  2. FUNCTION OF COMPONENTS 
    Component Function
    Pre-collision City Sensor
    • Acquires information about a preceding vehicle from a monocular camera sensor and laser sensor to perform pre-collision system control.
    • Sends the information display, PCS warning light and PCS warning message signal to the combination meter assembly based on pre-collision control information.
    • Sounds the pre-collision city buzzer based on pre-collision control information.
    Pre-collision System Cancel Switch Turns the pre-collision system on/off and changes the warning timing.
    Pre-collision City Buzzer Sounds according to signals from the pre-collision city sensor.
    Combination Meter Assembly
    • Displays the pre-collision system status (ON/OFF) and warning timing.
    • During a system malfunction, warns the driver by displaying a message in the multi-information display according to the nature of the problem in the system, blinking the PCS warning light and master warning light and sounding the meter buzzer.
    Hybrid Vehicle Control ECU
    • Detects the shift position signal and accelerator pedal opening angle and sends that information to the pre-collision city sensor.
    • Performs hybrid system output control based on information from the pre-collision city sensor.
    Skid Control ECU (Brake Booster with Master Cylinder Assembly)
    • Sends information such as the vehicle speed signal, stop light switch signal and brake control hydraulic pressure to the pre-collision city sensor.
    • Performs brake hydraulic pressure and emergency brake signal control based on information from the pre-collision city sensor.
    Steering Sensor (Spiral Cable with Sensor Sub-assembly) Detects the steering angle and steering direction.
    Yaw Rate and G Sensor (Airbag Sensor Assembly) Detects the yaw rate and acceleration of the vehicle and transmits signals to the pre-collision city sensor.
    Main Body ECU (Multiplex network body ECU) Sends destination information to the pre-collision city sensor.
    VSC OFF Switch Disables the pre-collision brake and pre-collision brake assist operation when the switch is turned on.
  3. OUTLINE OF PRE-COLLISION DETECTION 
    1. Collision detection
      1. The system determines in advance the possibility of a collision and whether the collision can be avoided based on road surface conditions and the position and speed of the preceding vehicle according to information about the preceding vehicle from the pre-collision city sensor.

        HINT: 

        For details about the system, see "Outline of Pre-collision System Control" and the function descriptions.

    2. Component
      Component Detection Content
      Pre-collision city sensor Obstacle in front (vehicle)
  4. OUTLINE OF PRE-COLLISION SYSTEM CONTROL 
    Control Condition Start of Control Sender ECU Receiver ECU Operated Parts
    Pre-collision warning Collision is possible Pre-collision city sensor Combination meter assembly
    • Combination meter assembly (warning display)
    • Pre-collision city buzzer (warning sound)
    Pre-collision brake assist Collision is highly possible Pre-collision city sensor
    • Combination meter assembly
    • Skid control ECU (brake booster with master cylinder assembly)
    • Combination meter assembly (warning display)
    • Pre-collision city buzzer (warning sound)
    • Brake booster with master cylinder assembly
    Pre-collision brake Possibility of a collision is very high Pre-collision city sensor
    • Combination meter assembly
    • Skid control ECU (brake booster with master cylinder assembly)
    • Hybrid vehicle control ECU
    • Combination meter assembly (warning display)
    • Pre-collision city buzzer (warning sound)
    • Brake booster with master cylinder assembly
  5. PRE-COLLISION ALARM CONTROL 
    1. When the system determines that the possibility of a frontal collision with a vehicle is high, a buzzer will sound and warning message will be displayed on the multi-information display to urge the driver to take evasive action.
  6. PRE-COLLISION BRAKE ASSIST CONTROL 
    1. When the system determines that the possibility of a frontal collision with a vehicle is high, the system applies greater braking force in relation to how strongly the brake pedal is depressed.
  7. PRE-COLLISION BRAKE CONTROL 
    1. When the system determines that the possibility of a frontal collision with a vehicle is high, the system warns the driver. If the system determines that the possibility of a collision is extremely high, the brakes are automatically applied to help avoid the collision or reduce the collision speed.
      NOTE:

      When the system detects that the driver is attempting to cancel operation of the system by performing operations such as the following, pre-collision brake control will be canceled.

      • The accelerator pedal is depressed strongly.
      • The steering wheel is operated quickly.
  8. VSC OFF SWITCH 
    1. Turning the VSC OFF switch on disables pre-collision brake assist control and pre-collision brake control.

      HINT: 

      After pressing the switch, the PCS warning light in the combination meter assembly will illuminate and "VSC TURNED OFF PRE-COLLISION BRAKE SYSTEM UNAVAILABLE" will be displayed in the multi-information display.

  9. PRE-COLLISION SYSTEM (PCS) OPERATION CONDITIONS 
    1. The pre-collision alarm control, pre-collision brake assist control and pre-collision brake control can operate if all of the following conditions are met:
      • Pre-collision system is ON
      • PCS warning light in the combination meter assembly is not blinking
      • Shift lever is not in R
    2. If the following conditions are met, the pre-collision alarm control will operate:
      • Vehicle speed is between approximately 15 km/h (10 mph) and 140 km/h (87 mph)
      • Relative speed is approximately 15 km/h (10 mph) or more
    3. If the following conditions are met, the pre-collision brake assist control will operate:
      • Vehicle speed is between approximately 30 km/h (19 mph) and 80 km/h (50 mph)
      • Relative speed is approximately 30 km/h (19 mph) or more
      • VSC system is not disabled
    4. If the following conditions are met, the pre-collision brake control will operate:
      • Vehicle speed is between approximately 10 km/h (6 mph) and 80 km/h (50 mph)
      • Relative speed is approximately 10 km/h (6 mph) or more
      • VSC system is not disabled
  10. PRECAUTION FOR PRE-COLLISION CITY SENSOR 
    1. Conditions under which the system may operate even if there is no possibility of a collision.

      In the following situations the sensor may detect an object, causing the system to determine that there is a possibility of a frontal collision and operate.

      GTY566496Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *a When there is an object (traffic sign, guard rail, etc.) by the roadside at the entrance of a curve *b When passing an oncoming vehicle on a curve
      *c When passing an oncoming vehicle while making a left or right turn *d When approaching a low hanging object that may contact the vehicle, such as a banner or tree branches
      *e When there is a reflective object, bump, protrusion, etc. on the road surface *f When rapidly closing on a preceding vehicle
      *g When rapidly closing on an electric toll gate barrier, parking area barrier, or other barrier that opens and closes *h When approaching an overpass, traffic sign, billboard, etc.
      *i When the front part of the vehicle is raised or lowered *j When the sensor is misaligned due to a strong impact being applied to the sensor, etc.
      *k When there is a structural object (billboard, street light, etc.) at the top of an uphill road *l When there is a metal object (manhole cover, steel plate, etc.) at the bottom of a downhill road
      *m When the vehicle is hit by water or snow from a preceding vehicle, etc. *n When driving through dense fog or smoke
      *o When the vehicle is being parked in a place where there is a low hanging object at the height of the pre-collision city sensor *p When passing extremely close to an object (stopped vehicle, guardrail, etc.)
    2. Situations in which the pre-collision system may not function properly.

      The system may not function properly in the following situations:

      GTY598568Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *a When driving on roads with sharp bends or uneven surfaces *b If a vehicle suddenly moves in front of the vehicle, such as at an intersection
      *c If a vehicle suddenly cuts in front of the vehicle *d If the vehicle is skidding
      *e When the front part of the vehicle is raised or lowered *f When the windshield is dirty or covered with raindrops, condensation, ice, snow, etc.
      *g When the sensor is misaligned due to a strong impact being applied to the sensor, etc. *h When a preceding vehicle is a poor reflector of laser (the rear part of the vehicle lowered, very dirty, etc.)
      *i When a very bright light, such as the sun or the headlights of oncoming traffic, shines directly into the pre-collision city sensor *j When driving in inclement weather such as heavy rain, fog, snow or a sand storm
      *k When the surrounding area is dark, such as while in a tunnel or during nighttime - -
  11. PRE-COLLISION SYSTEM AUTOMATIC CANCELLATION 
    1. When a system malfunction is detected and the pre-collision city sensor cannot detect vehicles, pre-collision system operation will be canceled automatically.

      HINT: 

      When the system malfunctions or is temporarily disabled, the PCS warning light will blink.

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