LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2008 >> LX 570 >> Repair and Diagnosis >> Transmission >> Automatic Trans >> Automatic Transmission >> Automatic Transmission System >> Fail-Safe Chart
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Fail-Safe Chart

  1. Fail-safe 

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

  2. Fail-safe Control List 
    FAIL-SAFE CONTROL LIST

    Malfunctioning Part Function
    DTC P0717.
    Input Speed Sensor NT    		 During an input speed sensor malfunction, shift control is performed through the output speed sensor SP2 signal.
    During an input speed sensor malfunction, up-shift to 5th and 6th, Al-SHIFT* and flex lock-up clutch control are prohibited.
    DTC P0722.
    Output Speed Sensor SP2    		 During an output speed sensor malfunction, shift control is performed through the input speed sensor NT signal.
    During an output speed sensor malfunction, up-shift to 5th and 6th, Al-SHIFT* and flex lock-up clutch control are prohibited.
    DTC P0710, P0712, P0713:
    ATF Temperature Sensor    		 During an ATF temperature sensor malfunction, up-shift to 5th and 6th and flex lock-up clutch control are prohibited.
    Shift Solenoid Valve S1, S2, S3, S4 and SR The current to the malfunctioning shift solenoid valve is cut off and control is performed by operating the other shift solenoid valves. Shift control is performed depending on the malfunctioning shift solenoid valve as described in the table below.
    DTC P0748, P0778:
    Shift Solenoid Valve SL1 and SL2    		 During a shift solenoid valve SL1 or SL2 malfunction, up-shift to 5th and 6th and flex lock-up clutch control are prohibited.
    DTC P2714, P2716:
    Shift Solenoid Valve SLT    		 During a shift solenoid valve SLT malfunction, the current to the shift solenoid valve is stopped. This stops line pressure optimal control, and shift shock increases. However, shifting is performed through normal clutch pressure control.
    DTC P2757, P2759:
    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 and flex lock-up control, and fuel economy decreases.

    HINT:

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

    Shift Solenoid Valve Normal Operation Chart 

    SHIFT SOLENOID VALVE NORMAL OPERATION CHART

    Shift Lever Position Gear* Shift Solenoid Valve S1 Shift Solenoid Valve S2 Shift Solenoid Valve S3 Shift Solenoid Valve S4 Shift Solenoid Valve SR Shift Solenoid Valve SL1 Shift Solenoid Valve SL2
    D, S6 1st OFF ON ON OFF ON OFF ON
    2nd ON ON ON OFF ON OFF ON
    3rd ON OFF ON OFF ON OFF ON
    4th ON OFF OFF OFF ON OFF ON
    5th ON OFF OFF ON OFF ON OFF
    6th ON ON OFF ON OFF ON OFF
    S5 1st OFF ON ON OFF ON OFF ON
    2nd ON ON ON OFF ON OFF ON
    3rd ON OFF ON OFF ON OFF ON
    4th ON OFF OFF OFF ON OFF ON
    5th ON OFF OFF ON OFF ON OFF
    S4 1st OFF ON ON OFF ON OFF ON
    2nd ON ON ON OFF ON OFF ON
    3rd ON OFF ON OFF ON OFF ON
    4th ON OFF OFF OFF ON OFF ON
    S3 1st OFF ON ON OFF ON OFF ON
    2nd ON ON ON OFF ON OFF ON
    3rd (E/B) ON OFF ON OFF ON OFF OFF
    S2 1st OFF ON ON OFF ON OFF ON
    2nd (E/B) ON ON ON ON ON OFF OFF
    S1 1st(E/B) OFF ON ON OFF ON OFF OFF
    1. Fail-safe operation for electronically malfunctioning shift solenoid valve (S1, S2, S3, S4 and SR).
      1. Fail-safe function

        If any of the shift solenoid valve circuits has an open or short failure, the ECM turns the other shift solenoid valves "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 the fail-safe mode, the gear position remains in the same position.

        HINT:

        • *: Actual gear shift (gear position) under failsafe operation.
        • X: OFF (the ECM stops sending current to the malfunctioning shift solenoid valve).
        • Electrical malfunction: Condition is shown to the left of the "→".
        • Fail-safe mode: Condition is shown to the right of the "→".
        • E/B: Engine brake

        Shift Solenoid Valve S1 Electrical Malfunction (P0973, P0974) 

        SHIFT SOLENOID VALVE S1 ELECTRICAL MALFUNCTION

        Shift Lever Position Gear* Shift Solenoid Valve S1 Shift Solenoid Valve S2 Shift Solenoid Valve S3 Shift Solenoid Valve S4 Shift Solenoid Valve SR Shift Solenoid Valve SL1 Shift Solenoid Valve SL2
        D, S6 1st X ON ON OFF ON OFF ON
        1st → 4th X ON → OFF ON → OFF OFF ON OFF ON
        3rd → 4th X OFF ON → OFF OFF ON OFF ON
        4th X OFF OFF OFF ON OFF ON
        5th X OFF OFF ON OFF ON OFF
        N → 5th X ON → OFF OFF ON OFF ON OFF
        S5 1st X ON ON OFF ON OFF ON
        1st → 4th X ON → OFF ON → OFF OFF ON OFF ON
        3rd → 4th X OFF ON → OFF OFF ON OFF ON
        4th X OFF OFF OFF ON OFF ON
        5th X OFF OFF ON OFF ON OFF
        S4 1st X ON ON OFF ON OFF ON
        1st → 4th X ON → OFF ON → OFF OFF ON OFF ON
        3rd → 4th X OFF ON → OFF OFF ON OFF ON
        4th X OFF OFF OFF ON OFF ON
        S3 1st X ON ON OFF ON OFF ON
        1st → 4th X ON → OFF ON → OFF OFF ON OFF ON
        3rd (E/B) → 4th X OFF ON → OFF OFF ON OFF OFF → ON
        S2 1st X ON ON OFF ON OFF ON
        2nd (E/B) → 4th X ON → OFF ON → OFF ON → OFF ON OFF OFF → ON
        S1 1st (E/B) X ON ON OFF ON OFF OFF

        Shift Solenoid Valve S2 Electrical Malfunction (P0976, P0977) 

        SHIFT SOLENOID VALVE S2 ELECTRICAL MALFUNCTION

        Shift Lever Position Gear* Shift Solenoid Valve S1 Shift Solenoid Valve S2 Shift Solenoid Valve S3 Shift Solenoid Valve S4 Shift Solenoid Valve SR Shift Solenoid Valve SL1 Shift Solenoid Valve SL2
        D, S6 3rd OFF → ON X ON OFF ON OFF ON
        3rd ON X ON OFF ON OFF ON
        3rd ON X ON OFF ON OFF ON
        4th ON X OFF OFF ON OFF ON
        5th ON X OFF ON OFF ON OFF
        5th ON X OFF ON OFF ON OFF
        S5 3rd OFF → ON X ON OFF ON OFF ON
        3rd ON X ON OFF ON OFF ON
        3rd ON X ON OFF ON OFF ON
        4th ON X OFF OFF ON OFF ON
        5th ON X OFF ON OFF ON OFF
        S4 3rd OFF → ON X ON OFF ON OFF ON
        3rd ON X ON OFF ON OFF ON
        3rd ON X ON OFF ON OFF ON
        4th ON X OFF OFF ON OFF ON
        S3 3rd → 3rd (E/ B) OFF → ON X ON OFF ON OFF ON → OFF
        3rd → 3rd (E/B) ON X ON OFF ON OFF ON → OFF
        3rd (E/B) ON X ON OFF ON OFF OFF
        S2 3rd → 3rd (E/B) OFF → ON X ON OFF ON ON → OFF ON → OFF
        3rd (E/B) ON X ON ON → OFF ON OFF OFF
        S1 3rd (E/B) OFF → ON X ON OFF ON OFF OFF

        Shift Solenoid Valve S3 Electrical Malfunction (P0979, P0980) 

        SHIFT SOLENOID VALVE S3 ELECTRICAL MALFUNCTION

        Shift Lever Position Gear* Shift Solenoid Valve S1 Shift Solenoid Valve S2 Shift Solenoid Valve S3 Shift Solenoid Valve S4 Shift Solenoid Valve SR Shift Solenoid Valve SL1 Shift Solenoid Valve SL2
        D, S6 3rd → 4th OFF ON X OFF ON OFF ON
        4th ON ON → OFF X OFF ON OFF ON
        4th ON OFF X OFF ON OFF ON
        4th ON OFF X OFF ON OFF ON
        5th ON OFF X ON OFF ON OFF
        6th ON ON X ON OFF ON OFF
        S5 3rd OFF ON X OFF ON OFF ON
        4th ON ON → OFF X OFF ON OFF ON
        4th ON OFF X OFF ON OFF ON
        4th ON OFF X OFF ON OFF ON
        5th ON OFF X ON OFF ON OFF
        S4 3rd OFF ON X OFF ON OFF ON
        4th ON ON → OFF X OFF ON OFF ON
        4th ON OFF X OFF ON OFF ON
        4th ON OFF X OFF ON OFF ON
        S3 3rd OFF ON X OFF ON OFF ON
        4th ON ON → OFF X OFF ON OFF ON
        4th ON OFF X OFF ON OFF OFF → ON
        S2 3rd OFF ON X OFF ON OFF ON
        6th → 4th ON ON → OFF X ON → OFF ON OFF OFF → ON
        S1 1st OFF ON X OFF ON OFF OFF

        Shift Solenoid Valve S4 Electrical Malfunction (P0982, P0983) 

        SHIFT SOLENOID VALVE S4 ELECTRICAL MALFUNCTION

        Shift Lever Position Gear* Shift Solenoid Valve S1 Shift Solenoid Valve S2 Shift Solenoid Valve S3 Shift Solenoid Valve S4 Shift Solenoid Valve SR Shift Solenoid Valve SL1 Shift Solenoid Valve SL2
        D, S6 1st OFF ON ON X ON OFF ON
        2nd ON ON ON X ON OFF ON
        3rd ON OFF ON X ON OFF ON
        4th ON OFF OFF X ON OFF ON
        4th ON OFF OFF X OFF → ON ON *rarr; OFF OFF → ON
        4th ON ON → OFF OFF X OFF → ON ON → OFF OFF → ON
        S5 1st OFF ON ON X ON OFF ON
        2nd ON ON ON X ON OFF ON
        3rd ON OFF ON X ON OFF ON
        4th ON OFF OFF X ON OFF ON
        4th ON OFF OFF X OFF → ON ON → OFF OFF → ON
        S4 1st OFF ON ON X ON OFF ON
        2nd ON ON ON X ON OFF ON
        3rd ON OFF ON X ON OFF ON
        4th ON OFF OFF X ON OFF ON
        S3 1st OFF ON ON X ON OFF ON
        2nd ON ON ON X ON OFF ON
        3rd (E/B) ON OFF ON X ON OFF OFF
        S2 1st OFF ON ON X ON OFF ON
        2nd (E/B) ON ON ON X ON OFF OFF
        S1 1st (E/B) OFF ON ON X ON OFF OFF

        Shift Solenoid Valve SR Electrical Malfunction (P0985, P0986) 

        SHIFT SOLENOID VALVE SR ELECTRICAL MALFUNCTION

        Shift Lever Position Gear* Shift Solenoid Valve S1 Shift Solenoid Valve S2 Shift Solenoid Valve S3 Shift Solenoid Valve S4 Shift Solenoid Valve SR Shift Solenoid Valve SL1 Shift Solenoid Valve SL2
        D, S6 1st OFF ON ON OFF X OFF ON
        2nd ON ON ON OFF X OFF ON
        3rd ON OFF ON OFF X OFF ON
        4th ON OFF OFF OFF X OFF ON
        5th ON OFF OFF ON X ON OFF
        6th ON ON OFF ON X ON OFF
        S5 1st OFF ON ON OFF X OFF ON
        2nd ON ON ON OFF X OFF ON
        3rd ON OFF ON OFF X OFF ON
        4th ON OFF OFF OFF X OFF ON
        5th ON OFF OFF ON X ON OFF
        S4 1st OFF ON ON OFF X OFF ON
        2nd ON ON ON OFF X OFF ON
        3rd ON OFF ON OFF X OFF ON
        4th ON OFF OFF OFF X OFF ON
        S3 1st OFF ON ON OFF X OFF ON
        2nd ON ON ON OFF X OFF ON
        3rd (E/B) ON OFF ON OFF X OFF OFF
        S2 1st OFF ON ON OFF X OFF ON
        2nd (E/B) ON ON ON ON X OFF OFF
        S1 1st (E/B) OFF ON ON OFF X OFF OFF
    2. Fail-safe operation in the event of a mechanical system malfunction.
      1. Fail-safe function

        The ECM controls the gear position as shown in the table below when malfunctions occur.

        FAIL-SAFE FUNCTION

        DTC Code Condition Gear*1
        - Normal 1st 2nd 3rd 4th 5th 6th
        P0751 Shift solenoid valve S1:
        Stuck OFF malfunction        		 1st*2 1st*2 3rd 3rd 3rd 3rd
        P0761 Shift solenoid valve S3:
        Stuck ON malfunction        		 1st 2nd 3rd 3rd 3rd 3rd
        P0766
        P0776        		 Shift solenoid valve S4, shift solenoid valve SL2 or valve body (brake control valve): Malfunction 1st 2nd 3rd 3rd 3rd 3rd
        P0781 Valve body (1-2 shift valve): Malfunction 1st*2 1st*2 3rd 3rd 3rd 3rd
        P0729 Valve body (sequence valve). Malfunction 1st 2nd 3rd 3rd 3rd 3rd
        HINT:
        • *1: Actual gear shift (gear position) under failsafe operation.
        • *2: Under engine braking, downshifting to 1st or 2nd gear is prohibited.
scientia non olet · About LEMON Manuals