AUTOMATIC TRANSMISSION SYSTEM(for 2TR-FE) FAIL-SAFE CHART


  1. Fail-safe

    This function minimizes the loss of operation when any abnormality occurs in a sensor or solenoid.

    Fail-safe Control List
    Malfunction Part Function
    Transmission revolution sensor (NT) During a transmission revolution sensor (NT) malfunction, shift control is performed based on the transmission revolution sensor (SP2) signal.
    Transmission revolution sensor (SP2) During a transmission revolution sensor (SP2) malfunction, shift control is performed based on the wheel speed sensor signal.
    ATF temperature sensors (No. 1 and No. 2) During an ATF temperature sensor malfunction, up-shifting to 5th and 6th is prohibited.
    Shift solenoid valve SL1, SL2, SL3 and SL4 Stop the conduction of electric power to a failed solenoid and shift gears by turning on/off normal solenoids. If all solenoids are malfunctioning, gears will be selected through mechanical hydraulic circuits.
    Shift solenoid valve SLT

    During a shift solenoid valve SLT malfunction, the current to the shift solenoid valve is stopped.

    However, shifting is performed through normal clutch pressure control.
    Shift solenoid valve SLU

    During a shift solenoid valve SLU malfunction, the current to the shift solenoid valve is stopped.

    This stops lock-up control, thus decreasing fuel economy.
    Shift Solenoid Valve Operation when Normal
    Gear Position 1st 2nd 3rd 4th 5th 6th
    Shift solenoid valve SL1 ON ON ON ON OFF OFF
    Shift solenoid valve SL2 OFF OFF OFF ON ON ON
    Shift solenoid valve SL3 OFF ON OFF OFF OFF ON
    Shift solenoid valve SL4 OFF OFF ON OFF ON OFF
    Fail-safe Control Chart
    Gear Position under Normal Conditions 1st 2nd 3rd 4th 5th 6th
    Shift solenoid valve SL1 ON Malfunction (without Fail-safe Control)* 1st 2nd 3rd 4th 4th 4th
    OFF Malfunction (without Fail-safe Control) 1st to N 2nd to N 3rd to N 4th to N 5th 6th
    Fail-safe Control during OFF Malfunction Fixed in 3rd or 5th
    Shift solenoid valve SL2 ON Malfunction (without Fail-safe Control)* 1st to 4th 2nd to 4th 3rd to 4th 4th 5th 6th
    OFF Malfunction (without Fail-safe Control) 1st 2nd 3rd 4th to 1st 5th to N 6th to N
    Fail-safe Control during OFF Malfunction Fixed in 2nd or 3rd
    Shift solenoid valve SL3 ON Malfunction (without Fail-safe Control)* 1st to 2nd 2nd 3rd 4th 5th 6th
    OFF Malfunction (without Fail-safe Control) 1st 2nd to 1st 3rd 4th 5th 6th to N
    Fail-safe Control during OFF Malfunction Fixed in 3rd
    Shift solenoid valve SL4 ON Malfunction (without Fail-safe Control)* 3rd 3rd 3rd 4th 5th 5th
    OFF Malfunction (without Fail-safe Control) 1st 2nd 3rd to 1st 4th 5th to N 6th
    Fail-safe Control during OFF Malfunction Fixed in 2nd
    *: Fail-safe control is not actuated when an ON malfunction occurs.