DIFFERENTIAL SYSTEM


  1. FUNCTION OF MAIN COMPONENTS

    Component Function
    Rear Differential Electronic Differential Lock Case Sub-assembly Switches the rear differential between FREE mode and LOCK mode in accordance with signals from the 4 wheel drive control ECU.
    Rear Differential Lock Position Switch (Transfer Indicator Switch) Detects the rear differential position (FREE mode or LOCK mode).
    Transfer Shift Actuator Assembly*1 4WD Detection Switch Detects the transfer shift position (H2 or H4).
    L4 Detection Switch Detects the transfer shift position (L4).
    A.D.D. Actuator (Differential Motor Actuator Assembly)*2 A.D.D. Position Switch Detects the actuator shift position (lock or free).
    Differential Lock Switch Selects the rear differential position (FREE mode or LOCK mode).
    4 Wheel Drive Control ECU Controls the coil assembly in the electronic differential lock case sub-assembly based on the signals from each switch and the vehicle speed signal from the skid control ECU.
    Skid Control ECU

    • Sends the vehicle speed signal to the 4 wheel drive control ECU.

    • Sends the brake control operation condition signals to the 4 wheel drive control ECU.
    Combination Meter Assembly*3 Rear Differential Lock Indicator Light Illuminates or flashes to inform the driver of the rear differential lock system condition.
    ABS Warning Light Illuminates to inform the driver when the ABS function is not operating while the rear differential lock system is switching to LOCK mode.
    Combination Meter Assembly*4 Rear Differential Lock Indicator Light Illuminates or flashes to inform the driver of the rear differential lock system condition.
    ABS Warning Light Illuminates to inform the driver when the ABS function is not operating while the rear differential lock system is switching to LOCK mode.
    TRC OFF Indicator Light*5 Illuminates to inform the driver when TRC function is not operating while the rear differential lock system is switching to LOCK mode.
    VSC OFF Indicator Light Illuminates to inform the driver when the TRC and VSC functions are not operating while the rear differential lock system is switching to LOCK mode.
    Multi-information Display*6 Displays "TRC OFF" to inform the driver when TRC function is not operating while the rear differential lock system is switching to LOCK mode.

    *1: 4WD Models

    *2: Models with SD20BD or SD20CD type front differential

    *3: Models without VSC

    *4: Models with VSC

    *5: Models without multi-information display

    *6: Models with multi-information display

  2. SYSTEM CONTROL


    1. When all of the following conditions are met, the 4 wheel drive control ECU supplies current to the coil assembly in the electronic differential lock case sub-assembly to switch the rear differential from FREE mode to LOCK mode.


      • The L4 detection switch is on (transfer shift position L4).*1

      • The vehicle speed is 8 km/h (5 mph) or lower.*2

      • The differential lock switch is on (differential lock switch pushed).

      Tech Tips

      *1: 4WD models

      *2: The rear differential should not be switched from FREE mode to LOCK mode while the vehicle is turning or while the wheels are spinning.

    2. The 4 wheel drive control ECU uses the rear differential lock indicator light in the combination meter assembly to display the condition of the rear differential lock system.

      Condition Rear Differential Lock Indicator
      Rear differential lock currently switching (FREE mode to LOCK mode) Flashes slowly
      Rear differential lock switching complete (LOCK mode) Turns on
      Rear differential lock system malfunction Flashes fast

  3. DIAGNOSIS


    1. When the 4 wheel drive control ECU detects a malfunction, the 4 wheel drive control ECU records the malfunction and memorizes the information related to the fault. Furthermore, the 4 wheel drive control ECU blinks the rear differential lock indicator light in the combination meter to inform the driver.

    2. The 4 wheel drive control ECU will also store the Diagnostic Trouble Codes (DTCs) of the malfunctions. The DTCs stored in the 4 wheel drive control ECU are output to the Global TechStream (GTS) via the DLC3.

    3. For details, refer to the Repair Manual.