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System Description

WARNING: This page is about a different car, the 2006 Lexus RX 400h. However, it is still accessible from the selected car via links, so may be relevant.
  1. AFS (Adaptive Front-Lighting System) 
    1. The AFS operates to illuminate the best position for smooth driving by projecting the low beam depending on the vehicle speed and steering angle.
    2. Standard Operation
      1. The AFS ECU moves the low beam in the headlight considering the vehicle running condition, etc.
        AFS STANDARD OPERATION

        Vehicle Turning Condition Head Light (Right Side) Head Light (Left Side)
        Right turn while driving Turns to right by maximum 5° Does not turn
        Left turn while driving Does not turn Turns to left by maximum 15°
    3. Start-up Conditions
      1. The AFS starts operating when the following conditions are met:
        AFS START-UP CONDITIONS

        Items Conditions
        Shift Position Other than R and N
        Engine Running
        Headlight Comes on
        Vehicle Speed 30 km/h (19 mph) or more
        Steering Angle 12° or more (varies depending on the vehicle speed)
        AFS OFF Switch Not pushed in

        HINT:

        • The AFS continues operation as long as vehicle speed is kept above 6 km/h (3.6 mph) when operation has started once after vehicle speed reaches 30 km/h (19 mph) or more.
        • The AFS continues operation as long as steering angle is kept at 10° or more when operation has started once after steering angle reaches 12° or more.
    4. Operation Stop Condition
      1. The AFS stops operating if any of the following condition are met:
        AFS OPERATION STOP CONDITION

        Items Conditions
        Shift Position R or N
        Engine Stops
        Headlight Goes Off
        Vehicle Speed 5 km/h (3 mph) or less
        Steering Angle 9° or less
        AFS OFF Switch Pushed in
  2. Power Distributor: 
    1. The power distributor installed in the J/B No.2 uses the no- contact type relay with a semiconductor.
    2. By using no-contact type semiconductor relays, the power distributor has been made more compact and lightweight than the previous relay box containing contact type relays.
    3. In addition to the function of the conventional relay box (Engine Room J/B), the Power Distributor has a function to protect the Power Distributor circuit if over current is applied to the Power Distributor or overheating occurs. The Power Distributor also has a mode monitor terminal for external checking of the operating condition (normal or protect condition) of the Power Distributor.
      Fig 1: Identifying Power Distributor Mode Monitor Terminal
      G04114917Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    4. Relay Type:
      RELAY TYPE

      Relay Type Relay Type
      Head Light Relay (RH) Semiconductor Battery Fan Relay Semiconductor
      Head Light Relay (LH) Semiconductor IG1 Relay Contact
      DRL No.2 Relay Semiconductor RDI FAN No.1 Relay Contact
      DRL No.4 Relay Semiconductor RDI FAN No.2 Relay Contact
      Rear Defogger Relay Semiconductor IGCT Relay Contact
      Back-Up Light Relay Semiconductor BRK Relay Contact
      Horn Relay Semiconductor C/OPN Relay Contact
      A/C Water Pump Relay Semiconductor A/F Relay Contact
    5. When the semiconductor relay is operating normally, the mode monitor terminal outputs approximately 6.2 V. When the semiconductor relay operates in protect mode, the mode monitor terminal outputs about 2.0 V. However, the mode monitor terminal outputs for the overall operating condition of the power distributor, so it is not possible to specify the semiconductor relay during protect operation.
    6. When the fail-safe function operates, the power distributor performs the following operations:
      1. Stops the operation of the troubled semiconductor relay only.
      2. Stops the power supply to the troubled semiconductor relay circuit only.

        HINT:

        Normal semiconductor relay or circuit operates properly.

    7. While the fail-safe function operates, check for a short circuit in the following areas:
      1. Wire harness driven by relay on the terminal side and body ground.
      2. Inside the power distributor (including the semiconductor relay)
    8. The power distributor soon restores the semiconductor relay function, but if a load abnormality still continues, the power distributor again stops the semiconductor relay function. (except Rr-DEF Relay)
    9. The power distributor and the semiconductor relay function stop until the rear defogger switch turns on again. Then the rear defogger switch turns on again, the semiconductor relay function recovers, but if the load abnormality is not corrected by this time, the Power Distributor again stops the semiconductor relay function. If the load abnormality is corrected, the semiconductor relay function recovers when the rear defogger switch turns on again. (Rr-DEF Relay)
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