Automatic Transaxle System (For Hatchback) Fail-Safe Chart

Drivetrain. Yaris. Ncp93, 131
  1. FAIL-SAFE

Automatic Transaxle System (For Hatchback) -- Fail-Safe Chart



FAIL-SAFE
  1. This function minimizes the loss of ECT functions when any malfunction occurs in the sensors or solenoids.

    Malfunction Part
    Function
    Vehicle Speed Sensor
    During vehicle speed sensor signal malfunction, 4th up-shift is prohibited.
    Transmission Revolution Sensor (Speed Sensor (NT))
    During transmission revolution sensor (NT) signal malfunction, 4th up-shift is prohibited.
    ATF (Automatic Transmission Fluid) Temperature Sensor
    During ATF temperature sensor malfunction, 4th up-shift is prohibited.
    Shift Solenoid Valve S1 or S2
    During shift solenoid valve S1 or S2 malfunction, current to faulty shift solenoid valve is cut off and control is effected by operating normal solenoid valve.
    Shift control effect depends on failed solenoid as described in table below.
    Shift Solenoid Valve ST
    During shift solenoid valve ST malfunction, 4th up-shift is prohibited.
    Shift Solenoid Valve SLT
    During shift solenoid valve SLT malfunction, 4th up-shift is prohibited.
    Engine Coolant Temperature Sensor, Knock Sensor or Throttle Position Sensor
    During engine coolant temperature sensor, knock sensor or throttle position sensor malfunction, 4th up-shift is prohibited.

  2. Fail-safe chart for shift solenoid valve S1 and/or S2:
    Fail safe function:
    If either of the shift solenoid valve circuits develops an open or short, the ECM turns the other shift solenoid ON or OFF in order to shift into the gear positions shown in the table below.
    Manual shifting as shown in the following table must be done (In case of a short circuit, the ECM stops sending the current to the short circuit solenoid).
    Even if starting the engine in fail-safe mode, the gear position remains in the same position.

    Normal
    Shift Lever Position
    Shift Solenoid Valve S1
    Shift Solenoid Valve S2
    Gear
    D
    1st
    ON
    ON
    1st
    2nd
    ON
    OFF
    2nd
    3rd
    OFF
    OFF
    3rd
    4th
    OFF
    ON
    4th
    3
    1st
    ON
    ON
    1st
    2nd
    ON
    OFF
    2nd
    3rd
    OFF
    OFF
    3rd
    2
    1st
    ON
    ON
    1st
    2nd
    ON
    OFF
    2nd
    L
    1st
    ON
    ON
    1st

    Shift Solenoid Valve S1 Malfunction
    Shift Lever Position
    Shift Solenoid Valve S1
    Shift Solenoid Valve S2
    Gear
    D
    1st
    X
    OFF
    3rd
    2nd
    X
    OFF
    3rd
    3rd
    X
    OFF
    3rd
    4th
    X
    ON
    4th
    3
    1st
    X
    OFF
    3rd
    2nd
    X
    OFF
    3rd
    3rd
    X
    OFF
    3rd
    2
    1st
    X
    OFF
    3rd
    2nd
    X
    OFF
    3rd
    L
    1st
    X
    OFF
    3rd
    X: Malfunctions

    Shift Solenoid Valve S2 Malfunction
    Shift Lever Position
    Shift Solenoid Valve S1
    Shift Solenoid Valve S2
    Gear
    D
    1st
    ON
    X
    2nd
    2nd
    ON
    X
    2nd
    3rd
    OFF
    X
    3rd
    4th
    OFF
    X
    3rd
    3
    1st
    ON
    X
    2nd
    2nd
    ON
    X
    2nd
    3rd
    OFF
    X
    3rd
    2
    1st
    ON
    X
    2nd
    2nd
    ON
    X
    2nd
    L
    1st
    ON
    X
    2nd
    X: Malfunctions

    Shift Solenoid Valve S1 and S2 Malfunction
    Shift Lever Position
    Shift Solenoid Valve S1
    Shift Solenoid Valve S2
    Gear
    D
    1st
    X
    X
    3rd
    2nd
    X
    X
    3rd
    3rd
    X
    X
    3rd
    4th
    X
    X
    3rd
    3
    1st
    X
    X
    3rd
    2nd
    X
    X
    3rd
    3rd
    X
    X
    3rd
    2
    1st
    X
    X
    3rd
    2nd
    X
    X
    3rd
    L
    1st
    X
    X
    3rd
    X: Malfunctions