AUTOMATIC TRANSMISSION SYSTEM FAIL-SAFE CHART


  1. Fail-safe

    This function minimizes the loss of ECT functions when a malfunction occurs in a sensor or solenoid.

  2. Fail-safe control list

    Malfunctioning Part Function

    DTC P0717:

    Input Speed Sensor NCO

    During an input speed sensor malfunction, shift control is performed using the output speed sensor signal (SP2).

    During an input speed sensor malfunction, AI-SHIFT*1 and flex lock-up clutch control are prohibited.

    DTC P0722:

    Output Speed Sensor SP2

    During an output speed sensor malfunction, shift control is performed using the input speed sensor signal (NCO).

    During an output speed sensor malfunction, AI-SHIFT*1 and flex lock-up clutch control are prohibited.

    DTC P2742, P2743:

    No. 1 ATF Temperature Sensor

    		 During a No. 1 ATF temperature sensor malfunction, flex lock-up clutch control is prohibited.

    DTC P0973, P0974, P0976, P0977:

    Shift Solenoid Valve S1, S2

    The current to the malfunctioning solenoid valve is cut off and control is performed by operating the other normal solenoid valve.

    Shift control is performed depending on the failed solenoid as described in the table below.

    DTC P2714, P2716:

    Shift Solenoid Valve SLT

    		 During a solenoid valve SLT malfunction, the current to the solenoid valve is stopped. This stops optimal line pressure control and shift shock increases. However, shifting is performed using normal clutch pressure control.

    DTC P2757, P2759:

    Shift Solenoid Valve SLU

    		 During a solenoid valve SLU malfunction, the current to the solenoid valve is stopped. This stops lock-up control and flex lock-up control, and fuel economy decreases.

    Tech Tips

    *: In addition to the switching of the shift pattern through the pattern select switch, Artificial Intelligence Shift (AI-SHIFT) control enables the ECM to estimate the road conditions and the driver's intention in order to automatically select the optimal shift pattern.

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

    1. Fail-safe operation for electronically malfunctioning shift solenoid valve (S1 and S2).


      1. Fail-safe function

        If either of the shift solenoid valve circuits has an open or short failure, the ECM turns the other shift solenoid valve ON and OFF in order to shift into the gear positions shown in the table below. Also, the ECM stops sending current to the open or short-circuited solenoid.

        Even if starting the engine again in fail-safe mode, the gear position remains in the same position.

        Tech Tips

        X: OFF (the ECM stops sending current to the malfunctioning solenoid valve).

        Shift Solenoid Valve Electrical Malfunction
        Shift Lever Position Shift Solenoid Valve S1 Shift Solenoid Valve S2 Shift Solenoid Valve S1 and S2
        Shift Solenoid Valve S1 Shift Solenoid Valve S2 Gear Shift Solenoid Valve S1 Shift Solenoid Valve S2 Gear Gear when Shift Lever is Manually Operated
        D X OFF 4th ON X 1st 4th
        X ON 3rd ON X 1st 4th
        X ON 3rd OFF X 4th 4th
        X OFF 4th OFF X 4th 4th
        3 X OFF 4th ON X 1st 4th
        X ON 3rd ON X 1st 4th
        X ON 3rd OFF X 4th 4th
        2 X ON 3rd ON X 1st 3rd
        X ON 3rd OFF X 3rd 3rd
        L X OFF 1st ON X 1st 1st