FORWARD OBSTRUCTION WARNING (FOW) SYSTEM

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Outline

• The Forward Obstruction Warning (FOW) system recognizes a vehicle ahead using the forward sensing camera (FSC) installed to the windshield, and if the system determines that there is the possibility of a collision with a vehicle ahead, the system alerts the driver of the possible collision using the warning indication and warning sound.

  Warning
  • The FOW system may not operate normally under the following conditions:
    ― Driving at the same speed as the vehicle ahead.
    ― Visibility is reduced due to a vehicle ahead casting off water, snow, or sand.
    ― Heavy cargo is loaded in the trunk, luggage compartment, or on the rear seat.
    ― Ice, snow, or dirt is adhering to the windshield.
    ― Inclement weather caused by snow, rain or sand storms.
    ― Driving on a continuously curving road.
    ― Entering or exiting a curve.
    ― Driving on roads with repeated up and down slopes.
    ― Driving on poor roads or unpaved roads.
    ― Driving with headlights not illuminated at night or inside tunnels.
    ― Driving with taillights of a vehicle ahead not illuminated at night or inside tunnels.
    ― Two or more taillights of a vehicle ahead are illuminated at night or inside tunnels.
  • The FOW system is designed to detect moving four-wheeled vehicles, however the following objects are not included.
    ― Pedestrians
    ― Two-wheeled vehicle
    ― Stopped four-wheeled vehicle
    ― Standing trees
    ― Street lights or signal lights

  Caution
  • If the FSC aiming for the FOW system is not completed, the camera shot angle for the FSC cannot be recorded and the FOW system may not operate. When performing the following servicing, always perform the FSC aiming. Refer to the FSC aiming procedure in the workshop manual.
    ― FSC replacement
    ― FSC clip replacement
    ― Windshield replacement

Function

• When the estimated time calculated by the FSC until a collision occurs with a vehicle ahead decreases below the threshold, the FOW system displays the warning screen in the LCD of the instrument cluster and operates the warning sound. For details on the detection of the vehicle ahead and the method for calculating distance between vehicles, refer to the Forward Sensing Camera (FSC). (See FORWARD SENSING CAMERA (FSC).)

Driver operation determination function

  • Even if the estimated time to a collision with a vehicle ahead decreases below the threshold, the FSC determines that the driver is taking avoidance measures under the following condition and suppresses the alarm operation.
    ― Brake switch ON signal is received.

Personalization features

  • The following FOW system settings can be changed: Refer to the Workshop Manual for details on the personalization setting method.
    ― System ON (operational)/OFF (non-operational) (initial set value is ON)
    ― Operation timing (Near/Far) for FOW warning indication and warning sound (initial set value is Near)

System conditions display function

  • The FSC displays the system status in the instrument cluster LCD.

FOW switch | Condition | Indication on LCD
--- | --- | ---
ON (system activates) | System activates |
Vehicle ahead is recognized |
Estimated time to a collision with vehicle ahead decreases below threshold |
• FSC detects camera fogging • FSC detects camera soiling • Malfunction occurs in FOW system • Malfunction occurs in FSC |
OFF (system stops) | System stops |

Structural View

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System wiring diagram

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Block diagram

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Operation

Operation conditions

  • The operation is performed when all of the following conditions are met:
    ― FOW switch is on (system activates)
    ― Vehicle speed of approx. 30—145 km/h {19.0—90.0 mph} is being received from PCM
    ― Vehicle ahead is recognized and estimated time to collision with vehicle ahead decreases below threshold

Operation

  1. When the FSC recognizes a vehicle ahead, it sends the FOW system conditions indication request signal (vehicle ahead display) via a CAN signal to the instrument cluster.
  2. The instrument cluster displays the vehicle ahead screen in the LCD based on the request signal from the FSC.
  3. When the estimated time to a collision, which is calculated based on the distance and the relative speed between the detecting vehicle and the vehicle ahead, decreases below the threshold, the FSC sends the FOW system conditions indication request signal (warning screen display) and the warning sound request signal via a CAN signal to the instrument cluster.
  4. The instrument cluster displays the warning screen in the LCD based on the request signal from the FSC and the warning sound is activated using the buzzer in the instrument cluster.

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