CONTINUOUSLY VARIABLE TRANSAXLE SYSTEM SYSTEM DESCRIPTION


  1. SYSTEM DESCRIPTION


    1. The K114F (CVT) is a fully electrohydraulically controlled steel belt type continuously variable transaxle. This is a highly efficient transaxle that is controlled in conjunction with the engine, contributing to enhanced fuel efficiency and quietness without shift shock. In addition, the continuously variable transaxle has the following features:


      • Diagnostic function

      • Fail-safe function when a malfunction occurs

  2. FUNCTION OF MAIN COMPONENTS


    1. The main components of the K114F CVT system are as follows:

      Component Outline
      Continuously Variable Transaxle Assembly Shift Solenoid Valve SC Used to switch control of the shift solenoid valve SLU between forward and reverse clutch control and lock-up clutch control.
      Shift Solenoid Valve SL
      Shift Solenoid Valve SLU Performs forward and reverse clutch control or lock-up clutch control depending on the state of the shift solenoid valves SC and SL.
      Shift Solenoid Valve SLP Controls the oil pressure of the primary pulley.
      Shift Solenoid Valve SLS Controls the oil pressure of the secondary pulley.
      Transmission Revolution Sensor (NIN) Detects the primary pulley speed.
      Transmission Revolution Sensor (NOUT) Detects the secondary pulley speed.
      Transmission Revolution Sensor (NT) Detects the input turbine speed.
      CVT Fluid Temperature Sensor Detects the CVT fluid temperature.
      Oil Pressure Sensor Detects the CVT oil pressure for belt clamping force.
      Stop Light Switch Assembly Detects the state of the brake pedal.
      Park/Neutral Position Switch Assembly Detects the position of the shift lever.
      Shift Paddle Switch (Transmission Shift Switch Assembly)

      • Detects the driver's shift-up and shift-down operations in 8-speed sport sequential shiftmatic mode.

      • Operating this switch when the shift lever is in D changes the mode temporarily to 8-speed sport sequential shiftmatic mode.
      Shift Lever Assembly Transmission Control Switch

      • Detects that the shift lever is in M.

      • Detects the driver's shift-up and shift-down operations when the shift lever is in M.
      Combination Meter Assembly Shift Position Indicator Indicates the shift lever position.
      Malfunction Indicator Lamp (MIL) Illuminates or blinks to alert the driver that the ECM has detected a malfunction.
      ECM

      • Performs electronic control of the CVT system.

      • When the ECM detects a malfunction, the ECM performs diagnosis and memorizes the malfunctioning area.
      Integration Control & Panel Assembly (Pattern Select Switch) (SPORT) Operating this switch turns SPORT mode on or off.
      Airbag ECU Assembly Yaw Rate Sensor Detects the vehicle's yaw rate.
      Acceleration Sensor Detects the vehicle's longitudinal and lateral acceleration and deceleration.
      Brake Actuator Assembly Skid Control ECU

      • Transmits the vehicle speed and longitudinal acceleration signals to the ECM.

      • Transmits the operating states of the ABS and VSC to the ECM.
      Electric CVT Oil Pump (Oil Pump Assembly with Motor) Keeps CVT oil pressure at an adequate level while the stop and start system is operating.
      Oil Pump Motor Driver (Oil Pump Assembly with Motor) Controls the power output of the electric CVT oil pump (oil pump assembly with motor).
      DLC3 Used for connecting the GTS to read diagnostic trouble codes and ECM data.

      Tech Tips

      The airbag ECU assembly incorporates the yaw rate sensor and acceleration sensor.

  3. OIL PUMP ASSEMBLY WITH MOTOR OPERATION CONTROL


    1. When the engine is stopped automatically by the stop and start system, the engine stop and start ECU operates the oil pump assembly with motor installed to the continuously variable transaxle to produce optimal CVT oil pressure for enhanced response of the continuously variable transaxle assembly and smooth start-off when the engine is automatically restarted.

      Tech Tips


      • Refer to the stop and start system operation conditions.

        Click here

      • The oil pump assembly with motor operates when the CVT oil temperature is between 25 and 100°C (77 and 212°F).

      • When the shift lever is in P, R or N, the engine will not be stopped by the stop and start system.

    2. Check oil pump assembly with motor operation


      1. Connect the GTS to the DLC3.

      2. Turn the engine switch on (IG).

      3. Turn the GTS on.

      4. Enter the following menus: Powertrain / Stop and Start / Data List.

      5. According to the display on the GTS, read the Data List.


        Powertrain > Stop and Start > Data List
        Tester Display Measurement Item Range Normal Condition Diagnostic Note
        Oil Pump Status Oil pump assembly with motor status ON or OFF

        ON: Oil pump assembly with motor operating

        OFF: Oil pump assembly with motor not operating

        		 ON is displayed while the engine is stopped by stop and start control

        Powertrain > Stop and Start > Data List
        Tester Display
        Oil Pump Status
        Oil Pump Assembly with Motor Operation
        Shift Lever Position P R N D or M
        Brake Pedal Depressed Does not operate Does not operate Does not operate Operates
        Brake Pedal Released Does not operate Does not operate Does not operate Operates → Does not operate*

        *: The oil pump assembly with motor will operate until the CVT oil pressure of the front oil pump installed in the continuously variable transaxle assembly becomes higher than the CVT oil pressure of the oil pump assembly with motor.