LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2012 >> IS 250C Standard Trans >> Repair and Diagnosis (Single Page) >> Body & Frame >> Windows >> Power Window Control System (Diagnostics & Symptom Tests) >> Power Window Control System >> System Description >> System Description
April 5, 2026: LEMON Manuals is launched! Read the announcement.

System Description

  1. FUNCTION OF MAIN COMPONENTS 

    The power window control system consists of the following components:

    Component Outline
    Power Window Regulator Master Switch Assembly
    • Controls power window operation for front door windows and quarter windows.
    • When lock switch is set to lock position, window operation will be possible only for driver power window.
    Power Window Regulator Switch Assembly
    • Located on front passenger door window.
    • Switch controls front passenger window operation.
    All Window Switch (Sliding Roof Switch Assembly) Simultaneously operates front door windows and quarter windows when switch is operated.
    Power Window Regulator Motor Assembly
    • Receives switch signals and changes signals into motor activation. As a result, window position changes.
    • Also uses two Hall-ICs in the regulator motor to detect window position*.
    Sliding Roof Control ECU Assembly
    • Controls power window operation for quarter windows.
    • Sends metal top and quarter window-linked operation signals to power window regulator master switch assembly and power window regulator switch assembly.

    *: for Front Door Windows

  2. SYSTEM FUNCTION 

    The power window control system has the following functions:

    Function Outline
    Manual up and down function Function that causes the window to go up while the power window regulator master switch assembly or power window regulator switch assembly is being pulled halfway up and to go down while being pushed halfway down. The window stops as soon as the switch is released.
    Auto up and down function (Quarter windows have only auto down) Function that enables the front door windows to be fully opened or closed by one press and pull of power window regulator master switch assembly or power window regulator switch assembly.
    Remote up and down function Function that allows the power window regulator master switch assembly to control auto and manual up and down operations of the front passenger door window and quarter windows.
    Window lock function Function that disables power window regulator switch assembly operation when the window lock switch is pressed. The power window regulator switch assembly can be operated when the window lock switch is pressed again.
    Key-off operation function
    • Function that makes it possible to operate front power windows for approximately 45 sec. after the engine switch is turned off when the driver door or front passenger door has not been opened.
    • When 45 sec. have elapsed, or the driver door or front passenger door is opened after the engine switch is turned off, the key-off operation function will be disabled.
    HINT: If the driver door or front passenger door is opened during automatic window operation while the key-off operation function is on, the window will stop operating.
    Jam protection function (front windows only) Function that automatically stops the power window and moves it downward if a foreign object gets jammed in the door window during auto up or manual up*1 operation.
    Wireless transmitter-linked open*2, *3 Function that causes the window to go down while unlock switch on the transmitter is pressed for more than 3.0 seconds. The window stops as soon as the switch is released.
    Diagnosis Function that allows the power window regulator master switch assembly and power window regulator switch assembly to make a diagnosis for failed section when the power window regulator master switch assembly and power window regulator switch assembly detect a malfunction in the power window system. If a malfunction is detected, power window regulator master switch assembly and power window regulator switch assembly lights come on or blink to inform driver and passenger.
    Fail-safe Function that partially disables the power window functions if a pulse sensor in a power window regulator motor assembly (for driver side or front passenger side) has a malfunction.
    • Front door windows auto up and down function and remote control function are disabled.
    • Manual operation is possible using the power window regulator master switch assembly and power window regulator switch assembly.
    Metal top-linked up
    • If the metal top switch is held in the close position after the metal top has fully closed, the front and quarter windows fully close.
    • If the metal top switch is pressed to the close position again after the metal top is fully closed, the front and quarter windows fully close.
    HINT: This function operates regardless of the window lock switch condition.
    Metal top-linked down The front door windows and quarter windows are fully lowered before the roof operation starts.
    HINT: 
    This function operates regardless of the window lock switch condition.
    Door-linked up and down
    • When a door is opened with the front window fully closed, the window will automatically lower a slight amount and then fully close when the door is closed.
    Quarter window-linked operation
    • When the quarter window is lowered with the front window fully closed, the front window will automatically lower a slight amount and will fully close when the quarter window is closed.
    All power window manual up and down function Function that causes all the windows to go up while the all window switch (sliding roof switch assembly) is being pulled up and to go down while being pushed halfway down. All the windows stop when the switch is released.
    All power window auto down function Function that enables all the windows to be fully opened by one push of the all window switch (sliding roof switch assembly).
    • *1: w/ Occupant Classification System except Front Passenger Side
    • *2: w/ Occupant Classification System
    • *3: This function is set through the customize function, as it is off by default.
  3. POWER WINDOW CONTROL OVERVIEW 
    POWER WINDOW REGULATOR MASTER SWITCH ASSEMBLY (DRIVER SIDE WINDOW)

    Power Window Operation Condition
    Engine Switch on (IG) Engine Switch off
    (Key-off operation Permitted)
    Engine Switch off
    (Key-off operation Prohibited)
    Auto up
    (hold switch at auto up position)
    •*1 X
    Auto up ◦*2
    X*3
    X
    Manual up X
    Manual down X
    Auto down X
    Wireless transmitter-linked open*2, *4 X
    Metal top-linked up X X
    Metal top-linked down X X
    Door-linked up
    Door-linked down
    Quarter window-linked up X X
    Quarter window-linked down X X
    All power window manual up ◦ [X] X X
    All power window manual down • [X] X X
    All power window auto down • [X] X X
    • ◦: Power window operates (with jam protection for front windows only).
    • •: Power window operates (without jam protection).
    • X: Power window operation prohibited
    • *1: Jam protection will not operate if the driver door switch is held in the auto up position until the power window is fully closed. However, if the switch is held for 9.5 to 10.5 seconds and then released, auto up operation with jam protection will resume.
    • *2: w/ Occupant Classification System
    • *3: w/o Occupant Classification System
    • *4: This function is set through the customize function, as it is off by default.
    • The content in the square brackets indicates the operation when the window lock switch is on (locked). If an X is shown in square brackets, this indicates that this operation is prohibited when the lock switch is on.
    POWER WINDOW REGULATOR MASTER SWITCH ASSEMBLY (FRONT PASSENGER SIDE WINDOW)

    Power Window Operation Condition
    Engine Switch on (IG) Engine Switch off
    (Key-off operation Permitted)
    Engine Switch off
    (Key-off operation Prohibited)
    Auto up*1 ◦ [X] ◦ [X] X
    Manual up ◦ [X] ◦ [X] X
    Manual down • [X] • [X] X
    Auto down • [X] • [X] X
    Wireless transmitter-linked open*2, *3 X
    Quarter window-linked up X X
    Quarter window-linked down X X
    • ◦: Power window operates (with jam protection for front windows only).
    • •: Power window operates (without jam protection).
    • X: Power window operation prohibited
    • The content in the square brackets indicates the operation when the window lock switch is on (locked). If an X is shown in square brackets, this indicates that this operation is prohibited when the lock switch is on.
    • *1: w/ Front Passenger Door Auto Up Function
    • *2: w/ Occupant Classification System
    • *3: This function is set through the customize function, as it is off by default.
    POWER WINDOW REGULATOR MASTER SWITCH ASSEMBLY (REAR SEAT WINDOWS)

    Power Window Operation Condition
    Engine Switch on (IG) Engine Switch off
    (Key-off operation Permitted)
    Engine Switch off
    (Key-off operation Prohibited)
    Manual up • [X] X X
    Manual down • [X] X X
    Auto down • [X] X X
    Wireless transmitter-linked open*1, *2 X
    • •: Power window operates (without jam protection).
    • X: Power window operation prohibited
    • The content in the square brackets indicates the operation when the window lock switch is on (locked). If an X is shown in square brackets, this indicates that this operation is prohibited when the lock switch is on.
    • *1: w/ Occupant Classification System
    • *2: This function is set through the customize function, as it is off by default.
    POWER WINDOW REGULATOR SWITCH ASSEMBLY

    Power Window Operation Condition
    Engine Switch on (IG) Engine Switch off
    (Key-off operation Permitted)
    Engine Switch off
    (Key-off operation Prohibited)
    Auto up*2
    (hold switch at auto up position)
    •*1 X
    Auto up*2 X
    Manual up ◦ [X] X
    Manual down X
    Auto down X
    Wireless transmitter-linked open*3, *4 X
    Metal top-linked up X X
    Metal top-linked down X X
    Door-linked up
    Door-linked down
    Quarter window-linked up X X
    Quarter window-linked down X X
    All power window manual up ◦ [X] X X
    All power window manual down • [X] X X
    All power window auto down • [X] X X
    • ◦: Power window operates (with jam protection for front windows only).
    • •: Power window operates (without jam protection).
    • X: Power window operation prohibited
    • *1: Jam protection will not operate if the driver door switch is held in the auto up position until the power window is fully closed. However, if the switch is held for 9.5 to 10.5 seconds and then released, auto up operation with jam protection will resume.
    • *2: w/ Front Passenger Door Auto Up Function
    • *3: w/ Occupant Classification System
    • *4: This function is set through the customize function, as it is off by default.
    • The content in the square brackets indicates the operation when the window lock switch is on (locked). If an X is shown in square brackets, this indicates that this operation is prohibited when the lock switch is on.
  4. VEHICLE CONDITION-LINKED CONTROL OVERVIEW 
    POWER WINDOW REGULATOR MASTER SWITCH ASSEMBLY (EXCEPT LINKED OPERATION)

    Vehicle Condition Condition
    Power Window Operation
    (Including Remote Operation)
    Key-off Power Window Operation
    (Including Remote Operation)
    Manual Auto Manual Auto
    UP DOWN UP DOWN UP DOWN UP DOWN
    Metal top status unknown X X X X X X
    Roof panel closed,
    luggage door closed
    Roof panel closed,
    luggage door opened forward
    Roof panel half open,
    luggage door opened forward
    X X X X X X X X
    Roof panel fully opened,
    luggage door closed
    Other X X X X X X
    • ◦: Power window operates (with jam protection for front windows only).
    • •: Power window operates (without jam protection).
    • X: Power window operation prohibited
    POWER WINDOW REGULATOR MASTER SWITCH ASSEMBLY (FOR LINKED OPERATION)

    Vehicle Condition Condition
    Wireless-linked Operation*1, *2 Metal Top-linked Operation Door-linked Operation Quarter Window-linked Operation
    DOWN UP DOWN UP DOWN UP DOWN
    Metal top status unknown X X X X X
    Roof panel closed,
    luggage door closed
    Roof panel closed,
    luggage door opened forward
    Roof panel half open,
    luggage door opened forward
    X X X X X X
    Roof panel fully opened,
    luggage door closed
    X X
    Other X X X X X
    • ◦: Power window operates (with jam protection for front windows only).
    • •: Power window operates (without jam protection).
    • X: Power window operation prohibited
    • *1: w/ Occupant Classification System
    • *2: This function is set through the customize function, as it is off by default.
    POWER WINDOW REGULATOR SWITCH ASSEMBLY (EXCEPT LINKED OPERATION)

    Vehicle Condition Condition
    Power Window Operation Key-off Power Window Operation
    Manual Auto Manual Auto
    UP DOWN UP DOWN UP DOWN UP DOWN
    Metal top status unknown X X X X X X
    Roof panel closed,
    luggage door closed
    Roof panel closed,
    luggage door opened forward
    Roof panel half open,
    luggage door opened forward
    X X X X X X X X
    Roof panel fully opened,
    luggage door closed
    Other X X X X X X
    • ◦: Power window operates (with jam protection for front windows only).
    • •: Power window operates (without jam protection).
    • X: Power window operation prohibited
    POWER WINDOW REGULATOR SWITCH ASSEMBLY (FOR LINKED OPERATION)

    Vehicle Condition Condition
    Wireless-linked Operation*1, *2 Metal Top-linked Operation Door-linked Operation Quarter Window-linked Operation
    DOWN UP DOWN UP DOWN UP DOWN
    Metal top status unknown X X X X X
    Roof panel closed,
    luggage door closed
    Roof panel closed,
    luggage door opened forward
    Roof panel half open,
    luggage door opened forward
    X X X X X X
    Roof panel fully opened,
    luggage door closed
    X X
    Other X X X X X
    • ◦: Power window operates (with jam protection for front windows only).
    • •: Power window operates (without jam protection).
    • X: Power window operation prohibited
    • *1: w/ Occupant Classification System
    • *2: This function is set through the customize function, as it is off by default.
  5. SWITCH LED ILLUMINATION CONTROL OVERVIEW 
    POWER WINDOW REGULATOR MASTER SWITCH ASSEMBLY

    Vehicle Condition Condition
    Driver Side Switch Front Passenger Side Switch Rear Seat Switches
    Engine Switch on Engine Switch off Engine Switch on Engine Switch off Engine Switch on Engine Switch off
    Key-off Operation Permitted Key-off Operation Prohibited Key-off Operation Permitted Key-off Operation Prohibited Key-off Operation Permitted Key-off Operation Prohibited
    Metal top status unknown Illuminates Illuminates Turns off Illuminates
    (Turns off)
    Illuminates
    (Turns off)
    Turns off Illuminates
    (Turns off)
    Turns off Turns off
    Roof panel closed,
    luggage door closed
    Illuminates Illuminates Turns off Illuminates
    (Turns off)
    Illuminates
    (Turns off)
    Turns off Illuminates
    (Turns off)
    Turns off Turns off
    Roof panel closed,
    luggage door opened forward
    Illuminates Illuminates Turns off Illuminates
    (Turns off)
    Illuminates
    (Turns off)
    Turns off Illuminates
    (Turns off)
    Turns off Turns off
    Roof panel half open,
    luggage door opened forward
    Turns off Turns off Turns off Turns off Turns off Turns off Turns off Turns off Turns off
    Roof panel fully opened,
    luggage door closed
    Illuminates Illuminates Turns off Illuminates
    (Turns off)
    Illuminates
    (Turns off)
    Turns off Illuminates
    (Turns off)
    Turns off Turns off
    Other Illuminates Illuminates Turns off Illuminates
    (Turns off)
    Illuminates
    (Turns off)
    Turns off Illuminates
    (Turns off)
    Turns off Turns off

    HINT: 

    The window lock switch on (lock) status is shown in the brackets.

    POWER WINDOW REGULATOR SWITCH ASSEMBLY

    Vehicle Condition Condition
    Engine Switch on Engine Switch off
    Key-off operation Permitted Key-off operation Prohibited
    Metal top status unknown Illuminates
    (Turns off)
    Illuminates
    (Turns off)
    Turns off
    Roof panel closed,
    luggage door closed
    Illuminates
    (Turns off)
    Illuminates
    (Turns off)
    Turns off
    Roof panel closed,
    luggage door opened forward
    Illuminates
    (Turns off)
    Illuminates
    (Turns off)
    Turns off
    Roof panel half open,
    luggage door opened forward
    Turns off Turns off Turns off
    Roof panel fully opened,
    luggage door closed
    Illuminates
    (Turns off)
    Illuminates
    (Turns off)
    Turns off
    Other Illuminates
    (Turns off)
    Illuminates
    (Turns off)
    Turns off

    HINT: 

    The window lock switch on (lock) status is shown in the brackets.